Spring Air Back supporter Pacific Breeze pillowtop not working out

I have a new Spring Air Back Supporter - Pacific Breeze Pillowtop that is giving me a lot of pain. I can not return the mattress as the store went out of business!
I am a 120lb side sleeper/sometimes back sleeper when I get flares of shoulder bursitis. Husband 155lb combo sleeper.
This mattress has 14.5G zoned coils. I sink down in the foam and then have hip and shoulder pain. Not really sure if is that the coils are too firm for me or the foam is too soft or combination of both. I have tried different latex toppers in different heights- 1", 2", 3" and also the Turmerry egg crate topper and lastly the 4lb gel memory foam topper (and a few less expensive memory foam toppers). None of the toppers worked out -I still sink down and get hip and shoulder pain. The latex toppers from SOL gave me a very weird feeling in the body- can’t even really describe it, but it wasn’t good. I liked the feel of the egg crate toppers, but they didn’t provide the pressure relief I needed. I also tried stacking the 4lb 1" with the 1" SOL latex topper and just sank into them. As you can tell, I do not like the sinking in the mattress feel.

I am back sleeping in my 8 year old mattress Stearns and Foster South Manor Luxury Plush Pillowtop mattress which never gave me this kind of pain and I do not sink “into” it (I was trying to replace it because it sagged so that I was sleeping on a bit of a diagonal which was not comfortable.)

Do you have any recommendations of mattresses I should look at and specific specs I should look for now for a new mattress? Mattresses that I have tried and returned- tempurpedic lux adapt medium hybrid (great for back but terrible on side). S&F lux estate medium pillowtop (arrive defective and store took it back, but I did not like the deep divets), Aireloom from Macys (came defective- foam sunk down and terrible odor- they took it right back), Chatham and Wells medium firmness was too firm for me and too hot- I exchanged that for the current Spring Air.

I have found all the latex mattress in the stores to be a little too firm for me. I found the 1" 4lb density memory foam topper hot so I am concerned about memory foam mattresses. Any help would be greatly appreciated. I don’t want to make another expensive mistake.

these are the specs for the Spring Air
Quilt

  • Layer of Comfort Fiber
  • FR Barrier
  • Layer of Super Soft Foam
  • Layer of Quilting Foam

Pillow Top

  • 1” Hypersoft Visco
  • 2” Gel Foam

Upholstery

  • 2” Comfort Foam

Unit

  • 884 Zoned Pocket Coil
  • 14.5 Gauge Unit
  • Foam Encased

These are the specs for the old Stearns and Foster
Quilting Layers:
• FlameGuard®
• 10-21 oz. New Zealand Wool (varies by size)
• 2” PrimaSense™ Gel Foam
• Gel Quilting Foam

Comfort Layers:
• 1.5" PrimaCool™ Gel Memory Foam
• 2.5" PrimaSense™ Gel Foam
• .5" SS Gel Foam
• 1" PrimaSense™ HD Gel Foam
• .5" PrimaCore™ Gel Foam

Support System:
• IntelliCoil™ Advanced
• 1504 Coil Count
• S&F Brass Air Vents
• Precision Edge™ System