What can I do about lower back pain/glute tightness while sitting in my 2005 Toyota Camry?

This is very stressful. I bought this car about 8 months ago and have been experiencing consistent lower back pain and tightness in my glutes/butt.

I tried all the seat adjustments and they don't help. I may experiment with different cushions soon.

Do you think installing a new chair a practical solution?