Struts (assuming you’re referring to the shock absorbers) have nothing to do with ride height. It wouldn’t surprise me if there is a very tiny leak in the system such that after a few days it has lowered a bit. If you disable the air suspension you definitely need to replace with coil springs. Otherwise you may need to charge up the air supply periodically.

 

My air suspension works as I can hear it occasionally coming on and off to maintain height and I can activate them from INPA and the height goes up and down as expected.

I recently replaced both front struts as they are not holding up anymore and can be compressed by hand. Wondering if my rear shocks are in the same condition. Mine used to have RFTs when I bought it used, since then I have replaced them with normal tires for better smoother ride. I know RFTs wear suspension components more than normal tires due to their stiff sidewalls.

Will refer to the air suspension layout and see which hoses are commonly replaced as for maintenance.