@BetterRed - we weren't picking on you - we just both happened to post a response at the same time
I understand you were just asking questions, however you are proposing one option which as I explained above is even worse than the current state - of creating a complete copy of Find Duplicates as it is today as "Advanced FD". That makes no sense at all for the reasons I explained above - none of us want to maintain that combination of features in a plugin for the long term. And I certainly dont want to have to maintain the "core" Find Duplicates code in two plugins, nor should anyone else be volunteering to do so.
I think an "Advanced FD" plugin which contained *only* the advanced features menu is indeed a good suggestion to make - but only if there is actual user demand of it. Also capink would have to agree to do all that work to create it, maintain it and support it. Which as they indicated above is not a guarantee in the longer term so it is their choice as to how worthwhile that all is to do for them.
BTW this discussion is in no way any kind of indictment about the code quality or amount of effort put into this Advanced feature by capink. I am extremely grateful to them for all the hours of effort that went into keeping this plugin alive through the python/Qt upgrades with others. But if this particular feature is very minimally used as suspected, then it needs to be removed for the long term benefit of the maintainers to respect their time.