I can recommend powerlevel10k with instant prompt enabled.

https://github.com/romkatv/powerlevel10k

Agreed. I lazy-load NVM to get around that:

  lazy_nvm() {
    unset -f nvm node npm npx
    [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
  }
  nvm()  { lazy_nvm; nvm "$@"; }
  node() { lazy_nvm; node "$@"; }
  npm()  { lazy_nvm; npm "$@"; }
  npx()  { lazy_nvm; npx "$@"; }

good call

if you care about perf, fnm is better/faster/cleaner than nvm. (also, mise is able to manage "all the things", not just node)

IME omzsh slowness usu relates to overloading it w plugins, which I've never found a need for...