Maybe it's a grass is always greener thing but I've been having issues with kbin that apparently other instances don't have. Furigana is supported on some Lemmy instances, I've had issues embedding links from Twitter/TikTok/Instagram/etc, I frequently interact with threads (preview content or upvote) and get redirected to an error page, goes on.
I did sign up with kbin for a reason though and I'm overall mostly satisfied. Having a good FAQ with how all the features of kbin work, what's on the roadmap, etc would be my biggest change.
Are you only interested in hosted applications? I've been using Keepass for years without any complaints. Though now that I'm seeing this thread filled with selfhosted vaultwarden comments, I might look into that though.