the code compiles & runs on all of their boards, exactly as intended in all ways except the seeed boards still not communicating properly with their UART screen. … Current top suspects on Arduino Discord are voltage-issues (the older boards likely have slightly stronger IO drive) & possibly timing issues with the screen maybe having less tolerance to timing imperfections than the PC or the other boards.
IIRC, she has tried the XIAO C3 board, along with several other seeed studio boards that she listed in her first post or two… iirc the included an S3, a c6 & an rp2040-based board.