Lots of Spam New User Registrations?

I’ve read through a couple of threads on this topic here and this is the least necro one I could find, so I figured I’d post here:

I’ve been running a small discourse forum for a few years with very little spam-profile-registration activity but after updating a week or so ago, it’s become a significant problem; I get >100 registrations per day now.

While the other anti-spam functions keep the actual spam posts to a minimum, these registrations are getting flagged as suspicious (as they rightly should) and it’s filling up my notifications such that I have to sift through all of them, ban-and-blocking as I go, to find the actual posts I need to approve/moderate.

So, my question is: did something change with the forum software recently, such as a change in a default setting, etc. that I need to mess with to get the previous behavior back, whether that’s preventing the spam registrations in the first place or just not putting them in my notifications so I can ignore them until they’re auto-deleted for inactivity?

EDIT: it looks like there’s a checkbox for “Staff must approve all suspect accounts”, which I’ve now unchecked and then reduced the “clean up inactive users after days” interval to be very short (I’m trying 2 days).