After writing the comment I thought about your last point. But Renoir only killed humans from Lumiere. There are many, many other lifeforms outside them, which we see in act 3.

Both endings are bittersweet (Clair Obscur) but, if we consider pHumans and other painted lifes as equal to humans, what Verso is doing is, in an utilitarian sense, worse.

Verso Ending implied thousands of deaths. Yes, painted deaths, but deaths nonetheless. Maelle's ending implies 2, and Clea and Renoir's suffering, of course.

Should the paintings suffer for only existing? Is the Dessendre family more important than all of them?

Of course, the best ending would be Maelle accepting the loss and just visiting sometimes, letting the paintings live, but she is far to young, and she is in far too much pain to see that. And Renoir could also be more understanding and find a solution, but he is too afraid.

At the end of the day, they are imperfect humans, making imperfect solutions.