I have been a software engineer for almost two decades and it's taken me three tries at reading and rereading the instruction on how to set Kagi as default search on iOS, because I missed the fact that I had to allow permission to use the extension WHILE browsing google.com for it to work, as it has to intercept the query to rewrite the URL.
When all it should've been is a "custom search engine" option like Firefox does.
Calling it "unobvious" is PR newspeak for jumping through the hoops to set up a Rube Goldberg machine to do a basic search.