Hay, Yea it’s the moded pinsDefinitions.h in your orginal post.
at c:~“\Arduino15\packages\Seeduino\hardware\mbed\2.9.1\cores\arduino
Same structure as yours on the variants folder path but the sense version. ie.
“\Arduino15\packages\Seeduino\hardware\mbed\2.9.1\variants\SEEED_XIAO_NRF5284_SENSE”
When I pasted them in from the zip ,compiler complained about renaming originals to “OLDvariant” & “OLDpins_arduino” and ADDING them from analogRead_LED.zip
Just messing with the ref to tweak the deviation +/- .03 deviation between the dvm and the serial print and OLED 
HTH
GL :-p