> Do I even know whether a specialist is good or not?

Of course but unless I misunderstood what you meant to say, you don't escape that by buying from AWS. It's just that instead of "sysadmin specialists" you need "AWS specialists".

If you want to outsource the job then you need to go up at least 1 more layer of abstraction (and likely an order of magnitude in price) and buy fully managed services.