Suspension issues, vibration?

Suspension issues haunt me every time I buy a car. This one has new wheels and tires. At 40-75 shaking increases, I didn't drive it past that. I balanced all wheels and they only needed minor adjustments. One of the rear tires was flat when I bought it. So, it may have been sitting flat for a while not sure. I tried to find a flat spot but I couldn't see any. I put gear in drive for the fronts to see about axles and videos are shows. No grease from any of the boots, suspension is solid, 100% tight, zero vibration in steering when you hit the brakes, all brakes have plenty left. No clicking or clunking from anywhere, just mainly vibration in cabin and floor. First three clips for driver side, last two for passenger. Both wheels/tires jump a bit but I think this is normal. No play in axles other than the normal play u see in any axle. No up and downplay.