"... I have to avoid $42k fines..."

You are not liable to COPPA enforcement agencies for any penalties whatsoever. COPPA applies to platforms, not content producers, that collect data. Goolag.

Goolag has lied in order to make palatable to it's market (youtubers) passing the expense of compliance with COPPA on to them. They certainly can ban, delete, or seek monetary compensation from you, but do not do so based on the authority derived from COPPA, which they alone are subect to.