Of course, there are a number of teachings from the GB which I have my doubts about. But for me, there are also a lot of teachings from the JWs which are possible, but not dogmatically the only way of interpreting matters.
For some on here though, no JW interpretation of a scripture is ever acceptable and they "move heaven and earth" to prove everything they teach has to be wrong, probably to validate their own rejection of JWs.
A lot of Trinitarians tend to take that view too. They refuse to accept the wealth of scriptures that indicate the trinity is a wrong, coming up with increasingly far-fetched or stretched "explanations" to negate every verse that contradicts the trinity, or at least suggests that it may not be a correct understanding.
It's that kind of "counter-dogmatism" that I don't like either, any more than the GB's own dogmatic view that they themselves are right in everything.
For example, Biahi says:
My Bible, The Living Bible, has a footnote for that scripture. It says, “this scripture reflects Solomon’s discourage opinion at the time. It does not reflect God’s truth on the matter.”
What makes that quote in the LB any more valid an interpretation than the NWT using Ecclesiastes 9:5? The writers/translators of the LB have simply asserted that.
The JWs have at least developed a doctrine based on numerous scriptures regarding the dead which is internally consistent. Is it 100% absolutely correct? I don't know - I'm not God, and I've never died and been resurrected to "test" the idea. But it is no more or less valid that simply saying "yeah well, what Solomon said doesn't reflect God's truth".
Also, regarding this:
I wonder how they interpret the fact that we can grieve the Holy Spirit?
In Genesis, God says to Cain that his brother's blood is "crying out" to Him. Does that mean blood is a Person? https://biblehub.com/genesis/4-10.htm
Also, the Holy Spirit is said to be "poured out" in numerous Scriptures. Can a creature or person be "poured out" to a crowd of people? Two examples:https://biblehub.com/ezekiel/39-29.htm , https://biblehub.com/acts/10-45.htm
This article has more under the heading "Impersonal attributes of the Holy Spirit": https://www.ucg.org/learn/bible-study-aids/who-god/who-god/holy-spirit-not-person
So assuming personification from a phrase like "grieve the spirit" is, while superficially understandable, not necessarily correct. You need to read the rest of the context of how the Spirit is used, described and/or appears in heavenly vision, etc, throughout scripture. And of how God himself speaks and acts. For me, doing so makes it clear the Holy Spirit is something God uses, not a separate, independently thinking and acting entity equal to God and Jesus.