I mean there’s Reddit ofc, as well as Twitter in its entirety, Discord is implementing some dumb updates, there are issues with Tumblr as well as everything to do with Meta, and I’m sure there are plenty more (and I haven’t even touched other digital media, for example the Sims). Why is it all happening in the span of about a couple months?
You don’t because they are only allowing a limited subset of characters and punctuation in actual usernames, so that’s not a problem. Display names (whether in general on by server) are another matter but always have been