A comment regarding stem insertion, for decades now, stems were marked with a minimum insertion line.
The formula was before thick risers, 5mm, 10mm were not a thing yet.
adding that stack I think points to the stem should insert an additional amount into the steerer, even if the threading is modest, there is a bigger lever at work.
So, with a plus 5mm spacer, 60 mm of insertion for argument’s sake instead of 55 mm.
many reasonable builders set the threaded area of the steerer to not have threading much beyond the headset assembly zone.
‘this fork with the excess threading suggests a replacement fork.
a “technomic” high rise stem would probably place the expander well below the steerer thread region.
a test don’t guess situation.

good that there was no vicious gravity storm here.