Wow... that was... a rather impressive post.
Hope it was fun! Analysis is my jam, but also sorry for length lol. I'm horrendous at short.
The "pretend" bothers me because it is not true. He wouldn't be a pretend god, he would be a real god and it still would be a shame to loose the human for it.
The "god you'd pretend to be" is dismissive of him and his vision, if you take the pretend out and say "the man you are is worth more than the god you could be" there you have statement that hits - and also reflects disregard for all the divines who have treated you as their playthings until now.
Intended gently from me--I think this is an interpretative choice on your end same as the version I described is an interpretive choice on mine. There are aspects of writing that are decisive and (DARE I SAY) absolute--but there are others that are more ambiguous. The latter work similarly to optical illusions where different audience members come away with different reads.
I don't take the 'god you pretend to be' line as purely literal, but as a reflection of what godhood/Gale trying to improve himself as much as possible through stuff would mean. By my read, it's less about functionally becoming a god and more about Gale abandoning himself the way he's feared everyone else would. Akin to outright burying the personal self.
If the line is taken in an exclusively literal sense, then it carries a connotation closer to what you described. But people don't speak in exclusively literal terms. For me, it was far more intuitive and tonally consistent for the line to suggest the player is elevating Gale's personal identity irrespective of power.
With the same intended gentleness, I do think it's important to be careful about what is claimed as objective fact versus what is interpretive choice. I figure you and I are fine and just sort of comparing notes here, but holy crap are some corners of the internet winding themselves up needlessly.
He totally is an ambitious wizards, is insanely curious, loves a challenge and needs to understand everything. That's what he is personally proud of and that never goes away, even in his human epilogues.
I told ya my ambition bit was controversial lol! ;P I may need to respectfully disagree, but like--the respect is sincere, I know this is an odd take and a lot hinges on personal definitions of ambition.
I figure Gale still genuinely loves magic in his human epilogue, but having seen a slew of other archwizards in the Forgotten Realms (including Daurgothoth, who far as I'm concerned is the pinnacle)--I'd argue the epilogue shows Gale finds contentment in a quiet, non-ambitious life teaching. He wants to share his knowledge with others and give them tools to find joy in magic for its own sake. He does offer to teach all subjects since he knows them, but that's not reasonable on a bunch of levels including 'humans do need sleep sometimes'.
Gale in his human ending doesn't appear focused on testing or pushing the limits of magic himself or impressing others, but in spreading understanding of magic among students so they can succeed to their best ability. It isn't about elevating himself to a singular and irreplaceable position (god!Gale) but specifically sharing tools and resources so that others have a better chance of success themselves. Combine this with Gale abandoning 'the Wizard of Waterdeep' (pompous, in his own words) to be just a normal guy with a normal first and last name... he seems finally at peace with being himelf.
Guy still loves magic, same as a writer might love writing or an artist might love drawing. Gale just doesn't need to be better than everyone else at it anymore to find personal value. At least, that's how I read the human ending.
If you look at the other wizards we meet, Rolan and Lorroakan, one can imagine why, wizard academia seems to be extremely cut-throat and place importance only on individual power and prestige. I'd go as far as to say this environment might be the reason for his mental health issues.
I analyzed this on another website in more detail, but 1) I agree 2) I think this is by design, by Mystra, who 5000% has motive given her own situation and psychology. It's okay if you prefer to read it differently ofc, this is another spot where loads of debate exists.
In that conversation Lorroakan mocks him for following around some adventurer and Gale begrudgingly says, that it's his choice to do so. I would just like for an opportunity to tell him how much I value him, his exposition and his expertly timed counter spells. It would be a nice opportunity to show the value of a group against that individualistic wizard behaviour too.
I saw the scene--personally idk if I'd call gale begrudging exactly so much as it's not something he's quite comfortable talking to Lorroakan about for the simple reason that Lorroakan is an asshole lol. But I'm with you on preferring to let Gale know the player character cares more and checking in.
I don't think she did. I figured that was the academic grapevine. You probably notice when a famed wizard suddenly goes into hiding and never leaves his tower. There probably was a lot of gossip.
See I figure people noticed he was missing, and there was gossip. But I also think Lorroakan had too many personal details not to have word from Mystra. Fits with Mystra's past behavior trying to warn followers away from doing certain things (IIRC she did some of this after the fall of Netheril and possibly a bit after Midnight ascended) along with her psych profile/what she fears for herself. Not including here because it would be an irredeemably long tangent on an already monstrous post, but I seriously loved analyzing Mystra. Wild narrative parallels, super manipulative and kind of tragic imo. But readings on Mystra are also controversial and subject to debate even without continuity questions. So again, all good if you have a different interpretation from me.
I hope not either, but there's actually a third example - Halsin - which makes me think we're looking at a real pattern. Fortunately they did sort of address that issue with Halsin by adding some new, more thoughtful content later.
YEAH I DIDN'T WANT TO GET AHEAD OF MYSELF SINCE I DIDN'T EXPERIENCE THAT BACKSTORY FIRSTHAND, BUT SEEMS LIKE ANOTHER CASE. I am glad it's been addressed somewhat at least, but agreed it seems like a pattern.

Denial of women's wrongs has been a running issue across multiple fandoms for me lately and it's so creepy.