@ancientjames Really like the small display bricks of yours.

Would be even cooler with a wireless enabled one, say a nRF52 or similar (a lot of extra work to create a new PCB and code)

The nRF52805 comes in a tiny WLCSP 2.482 x 2.464 mm package... But I have only tried to use there larger nRF52832 qfn48 6x6mm.
And a meandered inverted-F pcb antenna is going to be too big...