Why is that? There are 4 allen headed(?) bolts fixing the pulley to the gear, and the gear uses the big bolt to attach to the crank.
If you remove the pulley, the gear stays attached to the crank with the big bolt.
see
https://audi.7zap.com/en/rdw/audi+qu...46/1/105-5000/
Granted it's gonna be tight, but you can then swap a new belt on without the front bumper coming off or having to re-torque the crank bolt.
EDIT
And those four bolts may snap of course, but theoretically this is possible.