I wouldn’t buy another black bag because some other people have more. Many people have a number of brown bags. I’m happy with none.I do feel like I have a bit of a "hole" in the black bag department. I noticed most people have way more black bags then just 2.
It does seem like, as much as I LOVE the gabrielle there are times that it doesn't "fit" my outfit/the weather/the event BUT then my only other black option is the nano antigona, however the antigona is not very versatile (cross body wear only & its pretty small) it seems like the black marelle would fit into that "hole" perfectly
On the green side, if I send the Alma (the guitar strap it came with is useless for me) back there won't be any gap at all, I'll still have 9 green bags of all types.
It seems like my course is clear.... but I LOVE the green color so much!
But, you do say you need another black bag at times because the Gabrielle isn’t working well. Perhaps sell that, keep the green Alma you love and wait to find a black bag that is functional for how you live / dress and makes you as happy as your green bags do.