Agree up to certain levels but your examples are too specifc.

Understanding should come in different levels abstraction of what you are building,and managing.

There are different levels SREs, from beginner to say Fellow level.

Do you expect the Fellow level to understand nitty gritty details of each component his apps or services are interacting with and how each of them start? No. Especially when they have to deal with hundres or thousands of services each of them hosted by different teams, orgs, or different companies.

junior SREs, yeah probably got their hands dirty with those nitty gritty details you listed because they tend to deal with smaller or lower levels of components

So my point is, I agree withyour "Understanding" but not specific details as they differ per one's level of experience