God’s doctrine is supposed to be unchanging, and yet it changes continuously.
The doctrine is pretty unchanging. You sound like you have a misunderstanding of what is "doctrine" and what is not. I have no interest in convincing you of anything, but I will address some of what you have stated just so other people do not get the wrong idea. Much of what you have stated is incorrect.
The November 2015 policy was prophecy and the will of god, and then just a couple years later it wasn’t.
The November 2015 policy change was never prophecy. It was never characterized as prophecy. It was always merely policy.
Temple ceremonies are supposed to be directly from god, and yet those have changed massively over the years.
Temple ceremonies have never been directly from God. From the very beginning, the first time they were introduced in Nauvoo.
Polygamy was supposed to be the everlasting covenant, but then it wasn’t.
Nope. The everlasting covenant was about our doctrine of eternal marriage in general; polygamy was only included as far as it involved a sealing in the temple. The words describing this are the same as they were when Joseph Smith wrote them in 1843.
…Which is claimed to be doctrine and the will of god by the prophet, and then changes with the change in leadership.
Then you aren’t following the guidance of the prophet for every member to be a missionary.
What, do you think missionaries go around baptizing people at gunpoint? I'm no longer a full-time proselytizing missionary, but even when I was, forcing people to join the Church against their will was never a part of the program. What I'm doing right now is being a missionary, by rebutting the misinformation you are posting. Since you've clearly got no interest in coming back, all I can hope is that you will find peace in your heart and stop spreading misinformation about us.