Suspension issue or beyond?

So, my vehicle has been feeling rough, and it has recently tilted to one side lower. I thought it was just the ground itself but no I’ve looked at it in different parking places and when I stick my hand between the tire and the wheelhouse I can feel the difference in both sides and it’s definitely lower on the left side from a driver's point of view. It’s very rough on the road. It feels like my car is just going to bottom out of just fall off the wheels. My car makes hissing noises idk if it’s from the engine or the tires, but it also does it when I brake probably the loudest. The side that is lower. The front wheel on that side makes a whining noise and it gets louder as I accelerate faster. I just recently replaced the coil-overs with the same brand just brand-new ones which are BC racing coil-overs and it did not fix the problem at all. And now it just seems to be getting worse. At this point I have no idea what is going on with my car, there are no warning lights. It could be the chassis, I don’t know. Every mechanic just says everything looks fine, it’s not and I just want a professional’s help who’s not here to just run me my money and tell me it’s all good until I break down and come back to fix it.