Well, there are exactly two options with TikTok. Either you use the app or you don't. If you don't use the app then you probably shouldn't be making definitive statements about what content is on the platform.
If you do use the app then it will quickly (I mean within less than 1 hour of use) customize itself to your preferences. There is no "tweaking". Just by interacting with the app (swiping up on videos, viewing comments, allowing videos to replay, etc.)
So if you have been on TikTok for roughly 1 hour or more then you are getting a significantly customized experience that almost no one else on the platform is going to get. That isn't true on YouTube or really any other kind of media experience that existed prior to it. That is why older internet users can't really reason about it effectively and tend to make statements that sound out-of-touch to younger users.
One can use the app for any amount of time, and make any comment they wish.
If there's a critical mass of people making the same criticisms of the app, maybe the explanation isn't "you're using it wrong".
Somebody new to YouTube is going to think there's nothing on it besides Mr Beast, iPhone reviews and culture war nonsense, because that's what the front page shows to a signed out user. I imagine Tiktok is similar.