Yeah, one of the Discords I help with is >450k people. It's a gargantuan task to moderate, and a lot of it depends on having >20 people (which is another task in and of itself to vet >20 trustworthy people) that relies heavily on the community actively reporting things as well.
It can work, but for legal advice, I'd probably recommend another option.
I see our first edgy preteens have also made the jump over here too.