For anyone interested:
https://www.nkorth.com/uxn/Niju-0.1.pdx.zip
https://www.nkorth.com/uxn/niju-mono.rom

Source for my changes to niju: https://lists.sr.ht/~rabbits/public-inbox/patches/47646

The above Playdate build is using https://git.sr.ht/~rabbits/uxn-playdate @ 7b7a76c1 with minor modifications.