Merging solo-rpg with a regular ttrpg

Hey everyone :)

I'm starting to seriously consider designing my own RPG system, currently collecting ideas and mechanics; and was wondering what the community here would think about a ttrpg with a companion solo rpg that contribute to each other.

Character creation for the RPG could for example include an optional solo-rpg session that helps you connect emotionally to your character and establish their traits and personality and live path before the character joined a team of other heroes/players.

Or it's an optional part of regular gameplay: Your character in the ttrpg has dreams; those dreams are the solo sessions that you run yourself.

Maybe even crossing over: Those solo sessions, if they include a journal of sorts, could be handed to the GM of the regular sessions and they can use it to sprinkle in locations, NPCs, items, etc from the solo sessions. You dreamt being an explorer in a far away city? Discover the ruins of said city, 500 years later, in the regular ttrpg sessions.

That way the experiences and stories that you make while solo-rpging can be shared with more people and characters and influence the game world at large.

Please let me know what you think, I just had the idea right now and the only example of this that I could find is "Apocalypse Keys" with "it ends with you"