Catalina’s 64-bit-only update killed native support for many scanning devices, including some popular models still in common use today, particularly slide and negative scanners. According to this article, this week Hamrick released a new version 9.7 of its Vuescan scanner app, running under Catalina, and it offers support for thousands of older scanners from 42 manufacturers by reverse-engineering the drivers. You can see a complete list of supported scanners here.
I used Vuescan over a decade ago. It’s been around forever and is regularly updated. But it was a bit of a clunky beast.
(Not sure about today. But back when I scanned film I switch to the easier-to-use SilverFast software, which is also Catalina-compatible, but its list of supported scanners these days is minuscule.)