Have they fixed MacOS startup performance yet? ISTR some post about why faster CPUs were making emacs even slower on startup. Seems to have gotten worse over the years.

You boot Emacs once as a server. Then you connect through that server through emacsclient. It is your OS after all.

Sure, that's one approach. But it shouldn't take 45 seconds to spin up a new "emacs -nw" process, IMO. There's something pathological going on.