I am using starship for some time and it is great. The only advice is to avoid `custom` as it is slow: not too much but might be annoying.
`custom` spawns a child process of your shell, so it's probably being slowed down by a slow shell init script. If the custom script you're running doesn't require your full shell customization to work, you can provide a custom shell command [0], passing an argument to not use your shell config. For instance: `fish --no-config` or `bash --noprofile --norc`