Loved the game! I actually found the game quite simple for Playroom multiplayer. For this size of game, 20 player game lobby should be good(similar region). But the lag and jank is expected as you could be over synchronizing or sending more data than needed in later boss rounds. Its common for Jam and the time you all had.
Would love to help, look through the code and provide pointers.
All in All, great execution!
Tabs
Viewing post in The Cards You're Dealt jam comments
I'd be glad if you could help me after the jam ends! There's definitely a lot of stuff that feels like it could have been optimized, though because of the lack of time we had at out disposal and the lack of documentation (specifically for Godot) I had to improvise a bit in some parts of the synchronization process. Glad you liked it!