A long time ago I worked with someone who read 1 byte at a time from a socket because they insisted data was cached so the kernel was going to batch it magically somehow. It took me days to convince them to measure it.
Funny, I don’t know if you’re being sarcastic or sincere because I can’t tell the difference between that car and a Mustang or a Charger from the same decade.
Everyone telling you that it's fast because iTerm2 is slow. Terminal.app is already faster than iTerm2 and on par o very close to most other alternatives in terms of speed.
I also used Terminal until recently and don't use any of the advanced features alternatives provide. The main reason to switch from Terminal.app is truecolor support. The terminfo thing is annoying but I just setenv TERM in ssh config. Better split panes is nice. Configuration in a text file is a matter of taste, but documentation is good.