Starship can also be really really slow with the defaults, although that is not starship itself beings slow but it appears to sometimes call out to slow tools when display toolchain info.
I always turn all of the languages plugins off in Starship for this reason.
Honestly, I'm quite OK with bash+liquidprompt. It is probably an order of magnitude slower than these fancy new stuff.
Even with a huge monorepo and git stats displayed after every press of return it's OK (I win time at other places), but it's intriguing to have the same fast prompt display that I would otherwise have outside local git clone's directories.
What seems sexy about fish/starship is that there is built-in performance check / benchmark for slowdowns.
I always turn all of the languages plugins off in Starship for this reason.