It's not as bad as you think, I run the helm upgrade when patches come out, the backing store is S3 or managed SQL, it runs a nightly k8s cron called gitlab-backup which tarballs the whole thing into an s3 bucket with a single command restore should disaster strike. (This is part of the product, not a thing I wrote.)

I probably only babysit it for 30 minutes per year, including all the upgrades.

^ this. the last thing i want is to add to my workload. take my money and make my life easier, even if it means that for one hour every couple months i can't do anything

It depends how high you value your headaches, and how high, your org's downtime. Github not working accrues over the hourly rate of every developer affected, which is likely $70-$100 a hour. 10 hours of outage in a year affecting a team of 10 would cost north of $70k, enough to hire a part-time SRE dedicated just to tend to your Gitlab installation.