Hey @SignalRanger, I had a similar question a while back, but I was trying to figure out if a friend was using a fake account to follow me.
What worked for me was to compare the profile picture on TikTok with images on Google. If the person uses the same picture on other social media accounts, you might find their real name that way. Also, I checked the followers and following lists for any mutuals. If you have friends in common, that’s a strong hint.
Just a heads up, though – it’s easy to go down a rabbit hole, so try not to spend too much time on it!