I updated to macOS Sequoia last week and today I realised that the thumbnails are not showing?! Like cjay26, I edit off of Finder and the lack of support for OM/Olympus ORF files is a huge problem?!
The only workaround I have found so far is to convert them to DNG with Bridge and then the DNGs show up with thumbnails 🤷‍♂️
Also - I am guessing that the lack of OS support for ORF files somehow messes up Bridge as well, because random folders fail to load the Filters I use for sorting images - focal length, ISO, etc - certain folders just fail to load the list of Filters even tho they have been Checked to display.