Have you looked into distributing on Apple Arcade? I haven’t myself but it seems like it might be another potential source of income that doesn’t rely on ads/in-app purchases. I think Google Play has a similar game service?
From what I've heard, Apple Arcade won't even consider you for Apple Arcade unless you're already established and have made popular games in the past, and they're very selective even then. So there's probably no chance my game would be accepted for it.
This is one comment that corroborates that:
"It requires support for Mac OS and TV OS and committing to significant content updates every year for three years, at minimum. Revenue is based on how many people play your game compared to everything else on the platform.
Because of the contractual commitment and the need for marketing spend (If people don't play, you don't get paid), it's hard to recommend for a small developer without commercial experience, which is why Apple is rather particular about who they approve."[1]
