Can changing usernames cause issues on my MacBook Air?

I stupidly changed the username on my main account yesterday while using another admin account and left it that way overnight. I haven’t restarted the computer since. Today, when I logged back into the main account, I immediately noticed lagging and high CPU usage (though I was still able to log in). I did a quick search on my phone and learned that changing the username could damage user data. So, I logged back into the other admin account, changed the main account's username back to what it was before, and then restarted the laptop. Could this still cause any damage? Should I be worried?

It's been a while since I did this, and I haven't noticed any data loss or high CPU usage in the main account; all apps are running normally.

[Re-Titled by Moderator]