Oh awesome! Are you aiming for NoScript-like experience? Being able to easily whitelist domains, permanently and temporarily, is crucial. It's not clear from the page you linked if it has a whitelist feature.

Not easily, unfortunately. The extension relies on Safari's built-in permissions model, for technical reasons. It's possible to whitelist domains permanently, but not temporarily. https://underpassapp.com/StopTheScript/advanced.html

Looks like that whitelist is also only per top-level domain. E.g. it will allow all on Youtube.com or allow none, instead of allowing to block per script origin domain.

That sucks :( I'm really looking forward to switching back to Android.

Safari content blockers can do fine-grained blocking of external .js file loads, so you might want to look into one of those.

My extension differs from Safari content blockers in that it can block inline JS.