Don't get too excited. Many extensions do not work. It's as if Kagi needs to work on the code to make particular extensions work. I'm sure neither Firefox nor Chromium need to do that.
I have been using Orion and my interest arose because it purportedly supports Firefox and Chrome extensions. It supports some, but not most. When I post about the extension I need most, xbrowsersync, in the Orion Discord forum I am ignored. It doesn't work - nor does any other extension which syncs bookmarks. Given this lack of support I can see little advantage over Safari TBH.