That is a nice looking keyboard! Hope you find the motivation to keep working on it.

Thanks for sharing your progress!

Love th hhkb layout too!

I use a BT60v2 wireless PCB, the solder version that is the one that supports the HHKB layout. I have it in a kbdfans d60 lite case. If you go for this option I have a zmk github repo to program the PCB

You can also get a QK60 v2 from querykeys. I don’t recommended the wireless version as the programming software is proprietary and is very limited

Hope that helps