The waste drain coming out of the disposal must be higher than the waste line going back into the wall. The waste line can be lowered, but it must be done at its connection to the vertical drain line inside the wall. This is not an everyday DIY job.

Water does not flow up hill.

The waste arm needs to be lowered.

Luckily it is not usually that hard to cut through the back of the cabinet, then open the wall, lower the arm, and make a suitable repair of the wall and cabinet back.

Unless you have an open area under the sink no one is going to see the repair.