I like a lot of things about the Airpods Max, but like many have commented they tend to have a tight clamping force. Depending on your head shape and whether you wear glasses, this can end up being pretty uncomfortable after wearing them for awhile.
But there is one relatively simple trick to relieving some of this clamping force.
With the headphones out of their case, grasp each earcup and slowly spread them apart until the headband is almost straight. It will form a pretty obtuse angle between the headband and earcups. Hold it like that for 10 seconds, and then slowly release.
You’ll notice that the earcups are now permanently further apart when left alone, and won’t press against the sides of your head nearly as hard.
Note that the one drawback to reducing the clamping force on the sides is that there will be slightly more downward pressure from the headband since the sides aren’t supporting the weight as much.
If you stretch the headband too far and now find the Airpods too loose, just do the reverse. Gently push the earcups together with tension on the headband.