If I change my username, will searches for my old username still show me?

I've been having a problem with a stalker for the last few months and they know my TikTok username.

Now, I've made my TikTok private, made myself untaggable, blocked them (and their 4 alt accounts) and every other safety measure you can think of! But, I want to start posting again, and I already have posts on my account, plus reposts and I don't want to forsake it to make a new one.

So I planned on changing my username (and display name), maybe Privating my "easily searchable" posts that my stalker probably saw before I blocked them, and then start to post again. My question is, if they made a new account (one I haven't blocked yet) and tried searching for my previous username, would my TikTok account show up as a result of that search or is my old username 'completely forgotten' by the algorithm?