Sea Breeze (and like minded ones), why do think the Jews who became followers of Jesus primarily were Orthodox Jews, instead of Hellenized Jews like Stephen and Saul/Paul, and others (Acts 6:1-6; 8:4-5)? All of Paul's letters in our NT were written in Greek, and they were addressed to congregations which included Jews, and they were also addressed to individuals. Even the anonymous letter called "To the Hebrews" is in Greek. Furthermore, in one of Paul's letters Paul said it is OK if a honor one day as a special day (such as the Sabbath), and he said it is OK treat all days as alike. Note that Romans 14:5-6 (NKJV) says the following. "One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind. He who observes the day, observes it to the Lord; [a]and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks; and he who does not eat, to the Lord he does not eat, and gives God thanks." ["a. Romans 14:6 NU omits the rest of this sentence."] Furthermore, the NT says that Jesus said he is Lord of the Sabbath.
Some of the church 'fathers' wrote that there were Torah keeping Jewish believers in Jesus as the Messiah, such as the Nazarenes, Ebionites, and others, and there is evidence that some of those groups were still in existence in the 2nd century CE. Even our modern western Christianized Roman weekly calendar has both Saturday (the Sabbath day and 7th day of the week) and Sunday (the first day of the week) as the two days the 'weekend'. By the way, in Spanish the word ("sábado") for the seventh day of the week literally means "Sabbath" (and Spanish and Latin cultures are predominately Christian, not Jewish ones). To me this indicates that many early gentile Christians also observed the 7th day as a Sabbath (but perhaps I am wrong about that). See also https://en.wikipedia.org/wiki/Sabbath_in_Christianity . It says in part the following.
"Early Christians, at first mainly Jewish,
observed the seventh-day Sabbath with prayer and rest, but gathered on
the seventh day, Saturday, reckoned in Jewish tradition as beginning,
like the other days, at sunset on what would now be considered the
Friday evening. At the beginning of the second century Ignatius of Antioch approved non-observance of the Sabbath. ...
Beginning about the 17th century, a few groups of Restorationist Christians, mostly Seventh-day Sabbatarians,
formed communities that adopted the original interpretation of law,
either Christian or Mosaic, reminiscent of the early Christian church.
The Sabbath continued to be observed on the seventh day in the early Christian church.[note 1] To this day, the liturgical day continues to be observed in line with the Hebrew reckoning in the church calendars in Eastern Orthodoxy and Oriental Orthodoxy. "
The article also says the following. 'Jewish Christians
continued to observe Shabbat but met together at the end of the day, on
a Saturday evening. In the gospels, the women are described as coming
to the empty tomb Greek: εις μια των σαββατων, lit. 'toward the first [day] of the Sabbath', although it is often translated "on the first day of the week". ...
The 2nd and 3rd centuries solidified the early church's emphasis upon
Sunday worship and its rejection of a Jewish (Mosaic Law-based)
observation of the Sabbath and manner of rest. '
There is thus evidence that for a period of time a number of Jewish Christians honored both the 1st and 7th days of the week. Furthermore, consider the following.
Jesus (if he ever existed as a real person, instead of a myth) lived on Earth during the time of the second temple period of Judaism. During that time there were multiple sects of Judaism, including Essenes, those who wrote the Dead Sea Scrolls, Pharisees, Saducees, Zealots, and those who followed Jesus. Some of those lived in the time before the birth of Jesus, and some of those had some teachings which were long thought (such as after the year 1000 CE) to be uniquely Christian teachings, but which in the past 100 years have been discovered to predate the first century CE.
Regarding whether all (or even most) of the Christians of the first and second centuries CE believe that Jesus Christ had a bodily fleshly resurrection, instead of solely a spiritual resurrection, consider the following.
Some of the first century Christians believed that Jesus was resurrected as a spirit without a fleshly human body. A number of scholars say that the latter gospels (Luke and John) have passages saying that Jesus had a fleshly resurrected body (and/or that the resurrection body ate food) in order to refute those Christians were believed otherwise. The highly influential New Testament scholar Bart Erhman says the following at https://www.bartehrman.com/physical-vs-spiritual-resurrection/ says the following.
"Paul never mentions an empty tomb. ...
His letters do not address any conspiracy regarding a grave robbery. ...
According to Paul, it was Peter who saw the risen Jesus first–but again, no mention of how, when, or where. ...
A careful reading of Paul’s emphatic usage of Jesus’ “bodily”
resurrection reveals that Paul was repeatedly referring to Jesus rising
from the dead in a “spiritual” body (Romans 6:5, 2nd Corinthians 5:16-17, Philippians 3:10-11.)
That Jesus rose bodily
the dead was a foregone conclusion–what Paul sought to communicate with
the church at Corinth was the way in which Jesus lives on. What Paul means by “spiritual body” is perplexing.
Docetics believed that Jesus only appeared as a human being but was primarily spirit in substance. ... Docetism was an extreme byproduct of Gnosticism, which was arguably the
biggest opponent to the orthodoxy of the ancient Christian Church.
... It was the existence of these belief systems about Jesus that likely
motivated the orthodox Christian Church to canonize which writings
belonged and which ones needed to go away, a process which is described
and confronted here.
As belief in Jesus’ physical and/or spiritual bodily resurrection became the modus operandi for religious leaders, the other forms of Christian thought (especially Gnosticism, Docetism, and Arianism) were discredited or destroyed.
Fast forward to the cultural embrace of science and reason during a
period known as The Enlightenment in the 1800’s. During this period
Bible-loving Christians felt very threatened by those on the outside
looking in on the Christian institution, so the institutional
authorities doubled down on Biblical literalism."
See also https://jamestabor.com/why-a-spiritual-resurrection-is-the-only-sensible-option/ . it says in part the following.
'That is why finding the decayed bones of Jesus in an ossuary, as might
well be the case Talpiot tomb in Jerusalem, as I have argued here on
this blog and extensively in our book, The Jesus Discovery,
does not contradict the earliest faith in Jesus’ resurrection by his
first followers. What has happened is that people have conflated the later accounts
in the Gospels, especially in Luke and John, where Jesus clearly
appears as a “revived corpse” and even asks for food to eat–declaring
himself to be “flesh and blood,” with the much earlier views the gospel
of Mark (with no appearances of Jesus), the fragment ending of
the Gospel of Peter, and Matthew–that are much more compatible with
Paul’s earlier view (50s CE) of “seeing” Jesus’ spiritual body. The idea those who “sleep in the dust” awakening, or the sea “giving up” the dead that are in it, makes it crystal clear that resurrection of the dead
has to do with a transformed “heavenly” existence, not a revival of the
scant remains of those long ago turned to “dust and ashes” as the
phrase goes (Daniel 12:2-3; Revelation 20:13). One might also recall
that, according to Jesus, those who experience the “age to come” and the
resurrection of the dead, are transformed into an “angelic” state, no
longer male or female with physical bodies (Luke 20:34-38).'