Not sure how much it lines up with your specifics but I’ve used Neutron for ages and it supports WevDAV, SFTP, UPnP/DLNA amongst other things and sounds great (to my untrained eats anyway)

I’ve got both cloud backups for important docs etc and nas for anything else thanks

Thanks for the input everyone, I think I’ll go with rolling apps and OS into one drive as that seems inescapable and using fstab to mount my games drive inside /home/USER/ with a media drive left as just a drive. That leaves me with my smaller drive for Windows and a spare OS agnostic drive for both OS’s to access.