If you can hold off selling for a bit you will almost surely get more money for a maxi in a couple years. My SA said that in her boutique interest in the maxis is finally starting to return after a couple years of virtually no interest whatsoever. So if the trend really is beginning to shift back toward larger bags again, demand for the maxi in the resale market should bounce back with it. Plus, there will inevitably be at least a couple price increases in the next couple years, which always bump up the resale values of the flap bags too.
But if you are really itching to sell, I agree with many of the others who suggested you keep the vintage one and the newer one with the silver hardware and unload the newer one with gold hardware since that one overlaps with the other two the most.
In the meantime, enjoy your beautiful bags! ❤️