I ended up designing my own games to overcome this hurdle so I’ll just write about tools instead of games if you don’t mind. I know it’s impolite to brag about my own stuff but I prefer to talk about something I know well. Also, I can’t really call it totally my own stuff since I’ve been hacking left and right for so many years that now I don’t remember from where I picked some things and which ones I come up with alone. Anyway:
1-Quick brainstorm for worldbuilding. I think I first saw this in the Burning Wheel but wanted to keep things really short, so I ended up hacking from thereand other games until I got a list of about 8 questions. Also, after character creation, I ask the players about the choices they made and their expectations over those to create fronts, NPCs, and other setting elements.
2-Start with player-made character concepts, help them develop their character skills/items/abilities from them. The process so far resembles let’s pretend play enough for people to relax and enjoy themselves, as it makes them active part of the conversation and rewards their input with group acknowledgement.
3-Link their characters with one another and with the world they created. This crucial step prevents 99% of toxic play by giving players a motivation/goal to follow a story of their own instead of running amok and ruin the fiction for everyone else.
4-Set up a clear premise and as a GM, have a good idea on where it can go. After that, light prep like color, places, challenges and such only help to keep things going. Otherwise it all becomes following the players wherever their imagination takes them.
These principles can be taken to literally any game to make it a starting game for any player, as long as you explain properly the agenda of that game to the players. #2 can be reduced to ask the players about their character choices to make sure both the players and GM are in the same page about those. Like, if I choose to play a monk in D&D5e thinking of an anime-like frontline character I may be on my road to a world of frustration unless the GM is aware of my expectations and either embraces them or tells me to play it like that but use a fighter as a base instead.
The rest is about system mastery. All games are great, though I give it that some are better explained than others or are easier to explain once you understand what makes them tick. Some require you to understand a lot of mechanics before getting to play where in others you’re safe by learning them as you play, but none have really unsurmontable learning curves.