Not OP either but I moved back to kitty after giving ghostty a try. Kitty is pretty mature and it has tons of features. I don't use them all by any means, but enough that I missed them. It has all those features yet it feels so barebones: kitty is a delight.
Also not OP but Ghostty to my knowledge doesn't support predefined layouts, so that was my reason. I tried zellij, which is awesome, but Kitty turned out to be much easier to set up and ultimately use.
I'd say 100-200 ms is not horrendous but it can be much better without giving up on libghostty-vt :) check out Monstar.
Now, Monstar has a bizarre issue (at least in my setup) where it displays blank instead of capital A when used with Fixedsys Excelsior, for some reason. But hey it starts in under 10ms.