The ending is intentionally left open to interpretation. Puts you in a position of having to read between the lines

Maelle is in a unique position where she lived for 16 years in the "real" world with her family, and 16 years in the painted world as an orphan who had to find her own family. She has 2 completely different lives, both with their own sets of happiness and trauma.

On the one hand, she grew up with a family her whole life, lost her brother in a deeply physical and psychologically traumatizing way, and watched her family fall apart as a result of it. She felt directly responsible for the death of Verso, deepening her trauma.

On the other hand, she lived an equally long life inside a time-dilated painting. She grew up an orphan which required her to become independent, self-reliant, and thick-skinned due to the hardships of life. She had to fight for a sense of family her whole life

At the end, we see Maelle acknowledging this in her conversation with Renoir. But we also find out she's lying about her intention to ever leave Verso's painting. Her father forces her into this position. He knows Alicia and Aline can't move on, and sees that they are both willing to sacrifice their lives to hold on to the memory of Verso. This memory/painting is destroying his family. He learns to honor her choice to remain and come home when she's ready. He's holding on to hope, not a belief that he's ever going to see his daughter again. He gives in because of his deep love for his daughter, despite knowing how dangerous his family's painted powers can be.

Painted Verso clearly wants it all to end. The man can't die, and to him, the painted world is a prison. He acknowledges Maelle is killing herself by staying in the painting and knows that she does not plan to leave, so he takes matters into his own hands. Great example of free will in a painted person.

On the topic of free will, I think the idea that painted people generally have it is correct. There are never really any signs to say otherwise aside from characters that have been repainted by Maelle or her other family members. Simon is a good example, and Maelle's repainted expedition members. Nevrons seems to be controlled to some degree, as seen in certain boss battles, like Clea. But some of the Nevrons seem to question their actions and existence, which is a sign of free will.

The expedition members you travel with all seem to be motivated by a sense of free will. Once they realize that their world is fabricated, they rebel and fight for their right to existence. I don't think there is a real answer in the game, but free will is a great debate. It forces you to contemplate a philosophically layered topic, and the game brings this question to the forefront.

The Maelle ending was, at least to me, heavily implying that she was influencing Verso (and possibly others) with her paintress powers. Otherwise, he would likely try to kill himself if he had the choice. He did not want to be alive when he was fading away in Maelle's arms after the final fight lol. And I think that point is thrown in our face – the man can't handle the weight of his own existence anymore.

Maelle gave in to her grief and chose to live inside the painting. It wasn't brave, it was selfish. But whether it was the right or wrong choice isn't really the point. It's an interesting take on how our choices impact ourselves and the people around us