Sorry, I loaded the library and the Hello World example looks very different. My very brief look at both your code and the 3 examples I looked at indicate a lot of decisions and wiring choices have to be made.
I also don't see XIAO support, now that isn't normally a big deal, but this hardware seems to be ultra sensitive to what it is connected to.
I would get the display working with one of the example sketches before attempting to use a XIAO.