Sitting and Sleeping Help

In addition to the hypermobility I have POTS. THE thing that helps the most is having my legs elevated during the day and the head of my bed elevated at night. But both of those end up with me in positions where my hips are taking a beating and my hips are in a ton of pain.

I'm looking at getting a different sofa chair (my main base for the day) and wondering if anyone has recommendations on what to aim for- I need good back support, a way to keep my hips higher than my legs but my legs up, a stable base so I'm not using all the wrong muscles to sit etc. and/or specific pillows/props to stay in that 'neutral' space? As a side note I also need my elbows supported and higher than my hands. How?!

Then for sleeping... I'm a side sleeping trying to train myself to be a back sleeper because of the bed incline. But I have sleep apnea so they want at least my head to the side. Does anyone sleep successfully with the head of the bed raised and hypermobility (especially hip pain) and sleep apnea?

Thank you so much.