You do realize that number of simultaneous connections to different networks is an actual hardware thing, not just an arbitrary limit, right ? And what's the use case for more than 2 at the same time ?
I believe this is already supported. Haven't used esims extensively, but I see toggles for activating them on android. Not sure if there's a limit there. The real limit is only how many can be active at the same time.
If you preferent results to excuses, you get a dual sim phone and use whichever line has the most bars (I keep a Tmobile 5G access point for my computer stuff)