I'm running the Keepass2 packaged with Debian, which uses the mono port, and while I agree with your assessment that it looks like ass, it works perfectly, runs plugins, and integrates with the Kee addon in Firefox/Librewolf no problem.

Obviously I wish there was an official Linux version and I almost migrated to KeepassXC, but can't live without the built-in Sync function in Keepass original. While it was a bit of a beast to get set up initially, with some permission problems and the awkward process of installing plugins, I've now been using the mono version for over a year with no issues and can recommend it, for functionality at least.