I’ve heard nothing but good things about it. The only issue I’ve ever seen people call out is that by the very nature of the business, you don’t actually own the domain you register on Njalla. You’re basically renting it from them.

Basically. It wasn’t meant to act as an identification, but people kept using it that way (probably because every citizen gets one at birth, so it’s the easiest proof of citizenship).

Your threat model is unclear to me, so I’m a little confused as to why you don’t just use Firefox across all platforms. You could use multi-container support to stay signed in on certain things and clear cookies in others iirc.