Exactly what you wrote, with some context, something like "We officially confirm that these videos are not a problem for Grammarly, not about hacking and demonstrated behavior not affect the security and privacy of our product", nothing else. Thanks!
I do not think just tweeting at Youtube out of nowhere will work or is even appropriate (it would spam the feeds of a massive number of people). If you have a Twitter conversation with Youtube, I can probably have Grammarly chime in with a confirmation that it's not hacking. So please give me a link to such a conversation.
But in this thread, when I involved my friend (with whom we made several ЕdТech startups and who was also had a channel suspension issue), I had a conversation with @TeamYouTube https://twitter.com/TeamYouTube/status/1479514052984549385
Finally, after Grammarly's tweet and second appeal my channel was unsuspended. I think, help from maxltv was a key point in this process, so thanks again!