I haven't noticed any performance issues in vim to start with. It was fast on a 75MHz pentium for me. The syntax highlighting, same. No issues. I don't always use that though because I can't be bothered to set up anything much past the basic config.
That fell apart when people wanted vim to do some more modern IDE kind of things like all the “… on save” stuff (build on save, test, lint, etc). I think LSP support is native in neovim as well.
I believe vim merged asynchronous plugin support a while back though, so I’m not sure how different they really are anymore.
Just run make from another terminal...
I often use vim or nvim on disposable machines, so persistent undo is something very low on my list of things I want.