For me it blurs the thumbnail correctly but I have preview media on and it does not blur the preview. I wish this was an option as I like having the larger preview on mobile but don't want random porn while I scroll out in the world lol. Otherwise kbin has been nothing but wonderful. So glad to be here!
My recommendation over on Lemmy was a multireddit type of solution. It can be simply user customization so you can group together whatever you want but obviously this would take place once kbin can federate with lemmy etc.