I already have working 4G but the microSIM in my old Moto G4 I think
predates the very existence of 5G. I don't know if it has the nanoSIM
cutout or not but given its great age I am inclined to think not.
It was transplanted into that phone from a faithful Nokia that had an
unfortunate encounter with a bucket of water after falling out of my
shirt pocket. The Pixel 6 would probably tear my pocket off instead!
The new phone is 5G capable so it would be a shame to miss out on that
facility even if it will only work at 5G when I am in cities.