As @PinkyMacGodess says it's not likely happening.
Amazing that you still make them work with modern networks, wow. But I agree, it's sad that Apple didn't released any new versions of the Extreme's.
Mine was useless for quite some time back. New wifi is way better, and I have no problem with my set of D-Link's.
I'm really happy however that my 2x AirPort Express still works for streaming to old speakers. HomePod Mini's are not bad, and I'll probably buy more of them when Apple discontinue the Expresses that I use for my 4 x Creative speakers.
Yes, the Express AP's were amazing. Although out of four I owned, one rather dramatically blew a capacitor one evening as we all sat down for dinner. **BANG**, magic smoke, pieces of plastic for added effect. Quite dramatic. 💃🏻
But never went anywhere without one. (The drama queen was the older style that looked like a power brick, BTW) Wish I had picked up a few more of the last model.