nrfmicro VS mikoto

Either way, my advice is the same, first checkout this document which has known issues for a bunch of controller alternatives. Next, I'd recommend asking on the zmk discord since the zmk developers hang out there and are pretty active and helpful.

I'd give this a read. Should tell you everything you need to know.

Thank you! I have already connected the nrfmicro wireless controller to this board. It worked great!

Or this one https://github.com/joric/nrfmicro I made it to my board and works perfectly and it’s relatively easy to build even with just solder iron.

the nrf micro project is open source so you can review the schematic as a starting point https://github.com/joric/nrfmicro

If you can find nrf52 modules where you are then that's a good start, if you're not too scared of DIY intricate soldering then you can use them to build your own NRF micros. Ultimately the controller on these modules is the same as that of a nice!nano and if thus capable of running ZMK alone, there's not really a way as far as I know to pair them with a promicro or blackpill or similar to get a fully wireless solution.

What I know: https://github.com/joric/nrfmicro/wiki/Alternatives

slightly modified nRFMicro 1.4

Nothing I could say will be more thorough than this.

nice!nano isn't open source but this one is: https://github.com/zhiayang/mikoto

That's not possible with nice!nano, but the mikoto supposedly supports it

Mikoto 5.20 (Board: mikoto_520)

I'm talking about this one. It appears to be a controller with the pro-micro footprint that supports bluetooth 5, inspired by nice!nano. Has anybody used it in a real keyboard?