So I have the air susp. inactive warning
The front has dipped but on both sides not just 1
It does go up but slowly sinks back down so I'm confident the compressor is working
Does this mean both bags need replacing or is there another issue
I am new to RR and not sure how to diagnose correctly what I need to replace

Sounds like there is an air leak. Could be bags pipes or valves. Time to get the soapy water out before you fry the pump.