need advice from other editors

tiktok speeds up posts inconsistently and I’m losing my goddamn mind. My edits look great in the editing app and when downloaded but as soon as I try to upload to tiktok, the videos are sped up. But if they were just permanently sped up, I could live with that. But that’s not what’s happening; sometimes the videos are janky and too fast, sometimes they’re the original speed, and I have no way of fixing this or determining what my viewers will receive. If I try to edit with the time delayed to cater to tiktok, then my edits are wonky and there’s also an unknown probability that people who see my video will receive that messed up version. But if I edit normally, tiktok ruins my edit either way. What the hell are other people doing that I haven’t heard of? I’ve tried multiple editing apps and tiktok is definitely the controlling variable. I have noticed that the best edits I’ve seen are perfectly timed and nothing is out of sync, so how the hell are they doing it?????