I am on-call for a week every ~8 weeks. I get 500 € and two additional days of vacation for it. If I do get a call, the additional hours go to my time account.
Fair deal, I'd say. Only problem is that most of the applications are from vendors, so getting problems fixed is an ordeal.
> DDD is against the idea of having a single unified model; instead it divides a large system into bounded contexts, each of which have their own model.
If you have a large system it makes sense to divide it into smaller independent pieces. If you have a (micro)-service architecture you have distinct services, in a monolith you might have modules.
It is a hard problem to know where exactly the boundaries between services or modules should be, in any case DDD calls the things that make sense to decouple bounded contexts.