I'm attempting to quick search for files that without tags or without a specific tag and according to this post I should be able to do what I want but both methods listed in the post return zero results when I know there should be some. In fact, these two opposite searches both return zero results:
Maybe you are misunderstanding what searching for NO tags means (in that context)?, it means "In the tags database, with no tag" so for example with a label or a comment and no tag, it doesn't mean "all files without a tag", if that is what you are trying to do, to accomplish that you would need a search term like this:
?!tags:?* /E
Of course these examples listed are meant for the XY address bar, not live filter or elsewhere.
PS: To use inversions without requiring a switch you need this enabled (that's probably why both your examples provided identical results):
Ok. I see where I went wrong. This all started when I tried to use an old "Click and Search" Catalog Category with an exclamation point that did work last time I had used it (probably at least 1-2 years ago) and I wasn't aware that "Extended Pattern Matching" setting in the "Find Files and Branch View" tab was required for that now. Searching for what changed led me to find the post I linked and it wasn't clear that the search patterns there only searched items already in the tag database.