I love bright, fun colored bags!
I think once you have classic and neutral colors, expanding your collection to colors is ideal. Yes, a black bag can go with any outfit, but if every bag in your collection is black then there is going to be one that you tend to gravitate towards more than the others. Which leads to bags being unloved and collecting dust.
Personally, I love blues, purples and was super into pinks/blushes a couple years back. & I actually tend to reach for my fun colors more than my neutrals!
Another factor (at least for me, if I was in your shoes) - what’s the price? If you’re buying preloved and it’s a good deal, I say snatch it up! If the price isn’t all that amazing, maybe hold off and search for a better discount.
Keep us updated on what you decide!