I literally own my lastname as a Handshake TLD. I got it way back in September 2020, when they were still slowly releasing them. I love the idea of using first.lastname. It's great branding. However, my personal benchmark is can I hand a random person a business card and expect them to be able to visit my site. The answer to that right now is very clearly no and so it sits unused.

Adoption by default is a huge deal and you can't ignore it by saying that something "can" use it if you configure your router properly or this and that. The vast majority of people will never change it. Re. Firefox, I just tried switching it to NextDNS, but it seems like the default NextDNS resolver does not resolve Handshake domains.

Putting aside all the issues with DANE as a replacement to HTTPS, no browser supports it. This is why I don't use my handshake TLD for my personal/internal sites either.

Look, actual Handshake adoption would benefit me quite a bit, since I own a great TLD. I will keep an eye on adoption, but its very clearly a long road, and the project itself has a number of issues besides just adoption. It's cool, but you have to be realistic.