I actually did spend some time thinking about using FROST for payments over LN, where instead of multi-hop forwarding of HTLC, all parties run a signature scheme together to commit changes in an atomic manner. However, I think instead of FROST, MuSig2 might be a better choice.

I initially thought FROST like threshold signatures could have helped, but the problem is that some parties could collude and cheat the other parties - depending on thresholds etc. Therefore I think MuSig2 can work better. It can replace the need of multi-hop HTLCs. This of course takes away privacy goals of LN.

I did write about it a bit here: https://github.com/pool2win/ln-synctomic/ to log my thoughts. It is kind of a brain dump atm, and probably has some glaring mistakes 😃

I would love to join a brainstorming session/chat around this. I think a lot is possible for L2 payments using either MuSig2 or federations using FROST.