HTTPS for dotless domains (a bit of a misnomer but it can help in finding good reading material about it) should also work fine on the same browsers. That said, most dotless domains don't run it because they've historically not been given certs due to security concerns. As an example: https://uz./ likely just had the *.cctld.uz cert applied to the whole virtual server block and uz was just one of the names assigned to that block.

Bonus fact: https://. works on Firefox (triggers an A/AAAA DNS query for root) but not Chrome.