Orion uses the latest webkit release so it's usually ahead of Safari. The team is working to implement the web extensions API. It's not perfect yet but I use a number of extensions with no problems (Bitwarden, Dark Reader, Request Control, Sponsor Block) and a couple with minor issues (Reddit Enhancement Suite, Mate Translate).

Many extensions are not functional at the moment, owing to the incomplete extension API implementation, but the progress so far is very encouraging.

I also use Dark Reader on the iOS app which is pretty cool (haven't tried any other extensions on iOS).