FWiW the Phillips branded LED rope lights I got from Target seem to use connectors like yours. The female is seemingly exactly yours in different colored plastic, with one edge flattened. I’m looking at the extra bits that I disconnected to string the ropes together. the ropes with the male connectors are outside and it’s cold, but the little threaded storage cap provided to fit over the female end when disconnected from the rope isn’t flat on one side, but has the notch-style.
What I’m saying is that a male with a notch is compatible with a female with a flat, going by what I have. So maybe that widens your options. maybe. Also, searching for “Rope light connectors” might give you what you need. They sell a lot more of those than outdoor solar panels and pumps, I imagine.
The cords attached to these connectors have strings of alpha-numerical jargon printed on them that I could copy for you if you knew any of it was relevant.
