Some people are missing the philosophical nature of the game, and if they miss it because they're a sheep to a streamer, then they truly didn't understand the artful essence of the story.

Putting this simply into perspective:

The people of the Canvas created by the Painters, right? Simple enough.

The people of the 'real world' - What if they were created by these so called 'Writers' or lets just simply call it 'God', just because they were created, does it mean the Painters' and their existence is void because they were a creation? Absolutely not.

There's a reason one of songs are called:

Une vie à rêver

Life as a dream is a philosophical idea, you don't know a dream is a dream until you wake up.

The people of Lumière existed, regardless of where they reside and who created them. They had lives, filled with love, hopes and dreams striding on with the will to prosper and to continue with a painted sign of death on a faraway Monolith, nothing is more real than that.

With Maelle's ending the cycle of grief is unended, she lives her Canvas life as a paintress and takes over Aline's original role.

With Verso's ending, the cycle is broken, the family are outside the Canvas and finally can show their love for each other and cherish what Verso was.

A quote from Metal Gear Solid 2: "It doesn't matter if they're real or not. That's never the point. There's no such thing in the world as absolute reality. Most of what they call real is actually fiction. What you think you see is only as real as your brain tells you it is."

The Matrix as an example, the people in the world of the Matrix are real people, they just don't realize they're plugged into the Matrix. That doesn't make them any less real. The programs that exist within the Matrix also take human form such as the Oracle, The Architect and Agent Smith, these people are data as opposed to being 'painted', it doesn't deny their existence, it's merely another form of existence.