Thanks for changing to the Apple Silicon version, @Jessy, that should help with your speed issue!
For the Mailpit issue, please could you follow the steps here carefully once more, but delete all “mailpit” folders including the newer one named mailpit-1.24.1+0. We’ve seen that solve the issue in previous cases.
It’s likely that you have the Intel version of Mailpit instead of the Apple Silicon one, and those steps should take care of this for you.
https://community.localwp.com/t/mailpit-not-starting-on-osx/41889/6