Welcome!
Sounds like the shop is throwing parts at it... at your expense.
Some insights... the "check air suspension" warning is a sign something went wrong. Often left unchecked, the problem will worsen often overworking the compressor which will then require replacement.
But since the compressor has now been replaced, it is possible the original problem is still prevalent.
The front airs up first, then the rear. (It appears the front has raised but the rear has not, even with a new compressor and height sensor.) The system should run the compressor for up to 90 seconds in an attempt to raise the suspension to ride height.
If the check air suspension warning comes on immediately or within a few seconds of starting the car, the system has detected a hard fault and will quit. If the system 'times out' before the suspension has raised, the check air suspension warning will come on. This is usually indicative of a weak compressor or a leak - in the lines, solenoids or air bags. The system does not have enough reserve volume to make up for much of a leak, so it is likely any significant leak will not allow the air bags to inflate.
You may be able to assist in the troubleshooting by jacking the rear of the car up slightly (but below the full ride height) and try to let the car air up. Sometimes that will allow the system to air up but will not necessarily mean it's fixed.
When it does air up, one of the better health checks is to turn the suspension switch in the trunk to "off" and see if the suspension stays up overnight. If it does, try driving it and see if the suspension stays raised. You will often isolate a leak in doing this.