Agreed; modding obfuscated Java is impressive, but not quite on the level of modding in the (Nintendo) emulation community. The things that have been achieved with classic Nintendo titles are absurd, like adding high-performance online multiplayer to Super Smash Bro. Melee.
Said online multiplayer [0].
The devs also wrote a write-up here about how they handle the desyncs in netcode [1].
[0] https://slippi.gg/
[1] https://medium.com/project-slippi/fighting-desyncs-in-melee-...