Can anyone suggest a mattress to fit my needs?

Hello all, I am a 6'4" 350 lbs. 58-year-old man residing in the Omaha, Nebraska area. Due to sleep apnea and the use of a CPAP machine, I have been a back sleeper for the last five years.  I have spinal stenosis in my lower spine and painful neuropathy in both feet. Due to the latter two disabilities and one other, I spend approximately 18 hours a day in bed. When not sleeping (on my back), I'm usually lying down mostly on my side propped up on my left elbow while using my laptop or watching TV. 

I need a queen size bed and an adjustable bed frame for just myself. I'd like a hybrid one or two-sided mattress that will work on an adjustable frame. I am not picky, but I don't want to skimp on good quality m since I am a heavy guy and spend a lot of time in bed,   I like mid to firm, and a slight pillow top cushioning on the top surface would be okay, but is not a requirement. I would also like a lifetime guarantee or something close, as I feel it is often a testament to how well a manufacturer's mattress really is. A sleep trial is a must, but from what I've seen advertised that should not be a problem. During the last several weeks, I have tried to look for a mattress online. However, when I begin to research details  like the ideal number of coils and ideal gauge size to the various foam types with the best density and pounds per square footage, my brain begins to shut down. Unfortunately, I have  reduced cognitive thinking skills due to a TBI I received during an accident several years ago and is why I am unable to work ever again. I am hoping that with your expertise and experience with many mattresses, you might be able to suggest a mattress that will meet my needs. I hope I've provided enough information for someone to do that. I would really appreciate any good suggestions provided.

My weight 350lbs. Queen size and adjustable bed frame compliant Mid to firm with lite cushioning on top surface Budget—$3000 including frame, but want good value for money Omaha, Nebraska, but will purchase online.

Best regards, Patrick