Training about testing backups is still a bad idea: Why make someone do a job that purely verification? Those jobs eventually stop getting done, and it's hard to keep people doing them.

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.