I was lucky enough to work in a small eng team with 1 full-time dedicated QA person. One of the very few coworkers from my long career that I have really tried hard to poach away from whatever they were doing after our shared workplace went bust.

Yes, part of the job was to write and run manual test suites, and to sign off as the DRI that a certain version had had all the automated and manual tests pass before release.

But their main value was in the completely vague mandate "get in there and try to break it." Having someone who knows the system and can really dig into the weak spots to find problems that devs will try to handwave away ("just one report of the problem? probably just some flaky browser extension") is so valuable.

In my current job, I have tried for 5+ years to get leadership to agree to a FT QA function. No dice. "Developers should test their own code." Yeah and humans should stop polluting the ocean and using fossil fuels, how's that going?