Yes, mix-and-match is the way to go, depending on what kind of skills are available in your team. I wouldn't touch a mail server with a 10-foot pole, but I'll happily self-manage certain daemons that I'm comfortable with.

Just be careful not to accept more complexity just because it is available, which is what the AWS evangelists often try to sell. After all, we should always make an informed decision when adding a new dependency, whether in code or in infrastructure.

Of course AWS are trying to sell you everything. It’s still on you and your team to understand your product and infrastructure and decide what makes sense for you.