I used to start the car and it would rise up.

Now I start it and it stays lowered.

why?

I have talked to many owners, mechanics, and watched YouTube videos on coil over switch. (They all was like, “too expensive for a older vehicle, to much of a hassle, because when you get it all repaired it WILL fail again)

Don't buy an S-Class to put coilovers in it.

I will not change it out. I was thinking the same. It’s changes the ride.

Some possibilities:
Failure of the Airmatic relay.
Failure of the Airmatic fuse.

Start here https://w220.wiki/Airmatic#Compresso...28K40.2F7kO.29