I've made a new Custom View called 'NoTag' with the pattern 'Tags' 'Doesn't contain' 'Important' and so on for all the tag categories. Using that view doesn't make any difference, I still see duplicates of tagged messages.
A Custom View called 'OnlyTags' with reverse pattern 'Tags' 'Contains' 'Important' and all the other categories displays duplicates.
A Custom View called 'OnlyImportant' displays all mail tagged Important from both locations, 'Important' and 'Inbox'.
I have no idea if any of this is working as designed (leaving a question about why it would be designed like that).
I don't want to see duplicates, which doesn't seem unreasonable. How do I get rid of them? Ideally I want to see what's in the location 'Important' without seeing the same messages from location 'Inbox' (which is, tbh, how I'd expect Thunderbird to behave by default). Failing that, and as the Custom View clearly doesn't work sensibly, if there's nothing else I'll conclude I don't really care about tags, so a simple 'untag everything' would be ok as a last resort. But then, they were tagged for some reason, so really, being able to view them or not would be kindof handy. Having to wade through 10+ years of mail untagging individual messages is not a viable solution
