WordPress offers default roles, but it is entirely possible to create new, custom roles, with a selection of pre-existing and custom capabilities.
The infrastructure exists – it is a matter of whether plugin developers implement them correctly or not.
Privilege escalation happens when there is a missing / inappropriate capabilities check in the code.
At internet overall and a specially at a not very professional WP area it’s a normal practice now to hire some newbie’s and low-cost employee from faraway countries as Vietnam/India/Africa/etc.
<- Does not appreciate the implication that people from Vietnam, India, Africa, etc. are not professional.
If someone wants to cut costs by cutting corners when it comes to vetting and / or paying their employees less, then that is on them.
Of course, even if best practices are followed, it is still important to give the lowest possible access to each person, but that is highly context dependent, as it depends on what you need your employees to do.
Again, determining what the appropriate role is for various employees in a particular organization is well outside of the scope of these forums. If you need assistance compiling organizational charts, lists of duties and getting your code to correspond to that, pay someone (and make sure to vet them well beforehand).