>>8373406 (lb)

>Pilots aren't allowed to fly above 40k also

Pic is from adsbexchange a few mins ago.

FL410 can be seen quite often these days with commercial flights. Depends on technical specs of the plane, weather, route etc.

These days up to FL430 is not too unusual, even though business jets (if they can) much like to fly at those heights (and above as seen in the pic) since there's less traffic.