I am pretty middle of the road when it comes to blocking, I don’t block super often but do occasionally when I’m feeling it. In total over my time I’ve amassed something like 45 blocks, but looking at the list recently I realized that almost a third of those blocks are one user. I don’t like their vibe, but they are a prolific poster and account creator. The last time I counted I had twelve blocks for their accounts, but is there a way to set up a block or filter that will keep up with them making accounts with the same name on dozens of instances?

Run a small periodic program in the background that will search for users with that name pattern using the Lemmy Search API and block them.
Definitely an option, but probably more work than blocking them as I see them