Emacs has globally shared buffer state amongst the frames that share the same "base frame" (no idea what this is called) or the same socket (could be wrong here).

Anyway, you can start N emacs instances and they can all have individual buffer states.

Emacs is not primarily a TUI program (although it does have a TUI with the -nw). The TUI version of emacs lacks visual customizability and introduces unnecessary overhead (terminal!). Use the GUI.

Text insertion lag is something I haven't experienced since 2019. Config issue?

project-find-file might be slow because of low gc-cons-threshold. I know consult gets around this by temporarily raising the threshold. These days, you can use the feature/igc branch to make these operations faster (although they are pretty fast anyway).

If you think emacs lacks <fundamental feature X>, think again!