Facebook is a very different business from Twitter in 3 ways - firstly scale, they're more than 5x the size, secondly in engagement - they have enormous amounts of demographic and behaviour data about their users and they track them extensively across the web, and finally business model - Twitter does brand advertising whereas Facebook is much closer to point of sale, an advert on Facebook is likely to directly convert to a sale, whereas an advert on twitter is just mainly brand advertising - Facebook's type of advert is
far more valuable. So it's difficult to directly compare them.
But more importantly there's a big difference between how Facebook and Twitter work - Facebook is default closed, people can't interact with you unless you're putting yourself out there - either by friending people or joining a group, so there's a natural barrier against the spread of harassment, brigading and the toxic behaviour becoming public. There is a whole load of toxic neo-nazi stuff on Facebook, but it's out of view, and because ads are highly targetted there's no concern about brand safety. On Twitter it's default open, so if people are going around loudly spreading far right homophobic conspiracy theories about a violent attack on an elected official everyone is going to know about it - that's why Twitter has to be so careful.
There were a lot of people who have been in social media who explained in a lot of detail about how these things work when Elon first got involved. For example, Yishan Wong ran reddit back in 2012, at the time he had an extremely similar free speech maximalist view similar to Musk's current view. He did a very clear explanation of the dynamics of why that approach simply doesn't work - https://twitter.com/yishan/status/1514938507407421440 .