It’s not a matter of getting it “under control”. The trolls specifically create accounts with us to get us defederated, including verifying email and answering approval questions.
The thing that is meant to stop them (rate limiting) doesn’t work.
In short there is nothing we can do to get it under control short of blocking them when they slip through the cracks.
If that’s not good enough and you still want to defederate, well, that was their goal…