Why do you feel the need to keep config in git if you've got backups? I think the answer to that is the same reason that I'd rather keep a record of how the server is customised than a raw disk backup.
I do think containerisation and VMs are more overhead than they're worth in this case, but there's definitely a lot of value in having a step-by-step logical recipe for the server's current state rather than just a snapshot of what's currently on the disk. (I'd favour puppet or something similar).
> I keep config in git so that when I screw up, I can figure out how.
Right. Which is exactly why I want installing a new service, upgrading a library etc. to be in git rather than just backing up what's on disk. A problem like not being able to connect to MySQL because you've upgraded the zoneinfo database, or the system root certificates, is a nightmare to diagnose otherwise.
I do think containerisation and VMs are more overhead than they're worth in this case, but there's definitely a lot of value in having a step-by-step logical recipe for the server's current state rather than just a snapshot of what's currently on the disk. (I'd favour puppet or something similar).