However, VueScan [1] - something I hadn't used since my Epson scanner in the mid 1990s - saved the day! They support scanning for it, and after a quick purchase I was able to scan from it again.
This sounds like shilling for the company, but just posting here if anyone has a similar problem to me. I wanted to scan something but macOS 14 (and maybe 13 or 12?) wouldn't work with my Brother multi-function scanner... although the printing still works fine.
Otherwise I'm still very happy with this scanner - one software purchase and one set of toner cartridges in over a decade is pretty good total cost of ownership :)