After extensive looking the only selfhosted one that I can find that fits the bill is Seafile (latest update) which has a metadata based file storage function. Bear in mind setting up docker compose is a PITA but once you get it working (subject to license restriction - only 3 on free ‘pro’ tier) it works great.

Only other option that hits the same is the software I’m trying to replace: SharePoint (shudder). As much as Microsoft sucks the document libraries with columns are blooming powerful when combined with power automate. Good luck hunting!