Blizzard's way of doing names makes tons of sense and doesn't rely on an incredibly awful search to find people. You can name your account whatever you want, but they automatically give you a unique number (when paired with your name) so people can easily add you to their friends list. So you can sign up with the name "Bob" and they will give you "Bob#1234" for people to find you.
This way you don't have any worry about people having short usernames being special or unique. The issue is that this kind of username scheme works for gamers (that aren't trying to be standout/unique necessarily and just want their username), but I don't believe would be accepted by social media influencers whose usernames are their brand names.
Discord does the same thing with the discriminator, and if you're a Discord Nitro subscriber you get the ability to manually change it to whatever combo you like (as long as someone with the same username doesn't have that number).
This is an even better solution. I've never had a Battle.net account so was previously unfamiliar with this. I agree though, this is a good way to give people the display name they want which is the crux of my problem with making unique username the same as the display name.
This way you don't have any worry about people having short usernames being special or unique. The issue is that this kind of username scheme works for gamers (that aren't trying to be standout/unique necessarily and just want their username), but I don't believe would be accepted by social media influencers whose usernames are their brand names.