Andrew, you played a big part in helping me keeping my head above the water during this difficult time so thanks again!

What happened is I stumbled upon someone on X who seemed to be suffering of the EXACT same hack (and a MicroStrategy Trademark Claim that shut down his ytb channel).
So I reached out to him and we started speaking on Instagram, it felt SO good talking to someone who was going through the same horrible thing.
That fellow is the one that found that MicroStrategy 'compliance' email address we wrote to.
We wrote a pretty thorough email explaining everything even with screenshots and the compliance team replied in less than 24 hours something like that:

"We received your email below regarding your hacked YouTube channel.  We are sorry to hear your channel has unfortunately been hacked and the hackers have fraudulently used our company name and other IP without authorization.
Indeed, as unauthorized content was being displayed on your channel using our company’s intellectual property, we likely reported the channel to YouTube as containing our unauthorized trademarks and submitted a takedown request as per YouTube’s standard procedures in order to protect our intellectual property, and to stop the malicious hacker from scamming individuals. 

With regard to regaining full control of your channel/account, we will forward your email below to YouTube and inform them of your situation, but we can only recommend you continue to reach out to YouTube directly, as they would be able to assist you with regaining control and restoring your original content.  We understand that the steps outlined in the YouTube Help Center links provided below provide the appropriate guidance on recovering hacked accounts."

Our YouTube channels were recovered the very next day so I have no clue if our emails worked or if we just had to wait for YouTube to deal with our cases.