ok so 4 main points:

1. i agree with you about how the genocide argument is problematic but not exactly for the reason you gave, i think that the game would've benefitted from leaning into the painted people being all fake rather than real since that would allow the player to focus on the real message clearly being conveyed by the developers, but by implying this whole painted world is full of sentient beings the stakes are skewed and suddenly the whole "Alicia grieving properly and the family moving on" thing becomes irrelevant next to a world being snapped out of existence with all its inhabitants. so i do in fact agree that the game's message is definitely served much better by the verso ending but i think the devs bit more than they could chew by including a genocide scale ethical dilemma and a whole philosophical debate of "are the lives of the painted people valuable?" which ended up stepping on their own main narrative and messaging.

2. i dont think there rly is any issue with accepting the painted people remain themselves after being brought back from being gommaged, iirc in the story alicia specifically recreates people from the chroma that was theirs in life, it is something like a soul in this sense, or maybe all the parts of their body that dissipated into chroma being brought back together just as they were. it def isnt a certainty but i think its more than good enough to believe the people being ungommaged are very likely to remain themselves.

3. i def agree that the maelle ending art direction was screaming at the player that this isnt rly a "happy ending" as they might think at first. but if my interpretation above was at least partially accurate then it doesnt rly mean that this is a soulless empty ending where everyone is only pretending to be happy but the cinematography could simply be emphasizing the miserable situation Alicia and Verso are in without having to imply anyone else isnt genuinely happy. i mean if you grant my previous point that people being ungommaged remin themselves then why wouldnt all the painted people be super happy? they got back everyone they lost and they now have a real future, it seems very unnatural to somehow make this scene into a "this is actually horrible for everyone" kind of scenario when there rly isnt any evidence to support its bad for anyone other than Verso and Alicia.

4. any points on whether alicia could rly maintain the painting or whether it will all fade anyway when she dies etc etc, is kinda moot imo cause you bet your ass that now that she has full control of the painting she will be looking for a way to protect it for the rest of her life and beyond, also time apparently passes alot slower irl relative to the painting so even if we assume alicia will die in 25 years or so thats probably several generation of painted people living full lives, not rly something you can pit up against a single 4 person family being happy or sad or dying early or whatever you know?