I'd take a touch sensor on the back of the phone like is common on android devices over face id any day of the week, by the time the phone is level with your face it's already opened.
I have, but I think I unlock my device at home/work/maskless 99 times for each 1 time I need to do it with a mask. And 99 times I do that, I am generally in a place where I can just pull down my mask safely for 1s. That last 1 time I am OK to use the PIN.