Accessibility testing (with Microsoft Narrator as screenreader)? Somebody here with some practical guidelines?

As a front-end developer in a small business agency ( < 30 developers) I am trying to be better at accessibility testing and screen-readers are a must then.

I am a Windows user and also has access to a MAC and therefore I try to use NVDA (and Microsoft Narrator) and then go to MAC and use it's Voice over. Always feeling not quite 100% if my tests are good enough as I am not experienced screen-reader user and after reading a lot on them I found this useful page; https://webaim.org/articles/screenreader_testing/ - finding myself in this sentence here;

Screen reader users are one of the primary beneficiaries of your accessibility efforts, so it makes sense to understand their needs. Of course, you don't want to fall into the trap of thinking that accessibility is only relevant to screen reader users.

So - now to the question: how do you and your company cope with screen-reader testing ?

Do you have the needed competence level or do you out-source this (I think this needs to be tested manually but maybe somebody uses some advanced automatic tests too)?

And I found this one on MS Narrator:

Windows Narrator is not a real screen reader, it is a toy!

(https://stackoverflow.com/a/27756562/3365805) - but now we are in 2020 and I would like to think that MS Narrator should be "better" - what are your experiences here?

The objective here is of course 100% WCAG 2.0 A and 2.1 A compliancy (AA too in some cases).