One would only actually test the backups about twice a year just to be damn sure they are still resulting in restorable data. The rest of the year it's only worth keeping an automated process reporting whether or not the things are being made, and people keeping an eye on change management to be sure no changes are made to the known-to-be working process that can break it without the new process incurring an explicit vetting cycle. Gitlab wasn't apparently testing or engaging in monitoring what was supposed to be an automated process. That's where they got burned.
Process monitoring may be boring as hell, but it's seldom wasted effort, and will prevent massive, compounded headaches from bringing operations to a chaotic halt.
Nope. Nope. Nope.
You test every backup by automatically restoring from it in a sandbox and verifying its integrity and functionality in the restored state.
Backups are worthless unless verified for their intended use of recovering a functioning system.
And constant "this succeeded" messages don't scale well.
Instead, you make a machine verify the backups simply by using the backups all the time. For example, at work I feed part of our data pipeline with backups: Those processes have no access to the live data. If the backups break, those processes would provide bad information to the users, and people would come complaining in a matter of minutes.
Just like when you have a set of backup servers, you don't leave them collecting dust, or tell someone to go look at them every once in a while: you just route 1% of the traffic through them. They are still extra capacity, you can still do all kinds of things to them without too much trouble, but you know they are always working.
Never, ever, force people to do things they don't gain anything from. Their discipline would fade, just like it fades when you force them to a project management tool they get no value from.