Well, the video is very well done. I'll tell you what I think.
I think you're right about linking the latter rain to the Holy Spirit.
I came to the same conclusion.
Moreover, Revelation speaks of two witnesses, and they evidently represent the group that receives the Holy Spirit.
The outpouring of the first century is clearly a prophetic type that will be repeated, as Joel makes clear.
But there are some points to consider.
You argue that all Jehovah's Witnesses will receive it, and I think that is not correct.
All Jews were invited to the banquet, but only those who demonstrated faith and accepted the Messiah received it.
That is why only "a remnant was saved."
The majority of the brothers "have a zeal for God" but do not want to stop worshipping the governing body.
This became completely evident during the pandemic.
Those who allow themselves to be deceived by the "man of lawlessness" will not receive the Spirit. This is evident since they do not want to open their eyes, and the Scriptures say so.
I believe that only those whom God designates to be part of the "two witnesses" will receive the Spirit, along with a message to preach. We'll have to wait and see what happens.