You’re right. I didn’t consider the AppStore.
From the article, a $103 donation ended up as a balance of $33 in the TikTok account. If we assume TikTok has not negotiated a better rate (doubtful), then the math looks like:
Donation: $106
After App Store 30%: $74.20
After TikTok: $33
Which puts the TikTok commission at a (still egregious IMO) 55%