Not particularly knowledgeable in the undercurrents of “Teh Twitters”. But I afaict this is true.:

For people who may not have seen this yesterday:

I changed my handle to @TheRealHoarse

When an account changes their @, it changes only the name. All of their old tweets are still there.

So, scroll my timeline and you’ll find all my old posts.

— The Hoarse Whisperer (@TheRealHoarse) August 29, 2020