To the moderators here
I hope you are doing well.
Sorry for stating the obvious, but... spam is raining here since a couple days. Gah.
The other website where I post content, MTS2, has a "If you are human, DON'T fill this one" slot upon registration of new users. Bots automatically fill everything so they kinda betray themselves. Maybe it is something that could weed them off easy?
You all know your stuff well, so I am sure you will come up with a good solution. If this helps, good. I am not a coder so you know better than me. ^^
Have a good day.