Don't worry about this for now on tiktok is not a problem, but on other things it is, such as google play developer accounts etc.
I have the same problem as you and by using copied videos, it's hit or miss - sometimes I get originality strikes, sometimes not. I even tried recording the video myself while opening the YouTube page, but it got originality strike.
Other things I tried are AI upscaling but it was on 2 videos - 1 got originality strike and 1 didn't.
Dm me and lets exchange ideas, I am also doing tiktok Creativity program, I have 5 accounts.
Also I saw some kids monetizing by using CPA links. Do you have experience with that?
In that case, we won't need to have original videos.