Hello @tianaf, Welcome to Connect. Thanks for starting this discussion. It's a great question and one that I've thought about a lot. Like @sicko I have sleep apnea and use a CPAP which does throw a wrinkle into elevating your legs when sleeping. I'm a side sleeper by habit but do occasionally end up on my back which sometimes causes my sleep apnea events to be a little higher. I also have lymphedema and wear compression socks during the day so elevating my legs does help with the swelling. My problem is sleeping on your side when your legs are elevated can be a little uncomfortable.

My wife and I have a split California king adjustable bed and I elevate the feet on my side slightly above the heart. I also use a small pillow between the knees to make it a little more comfortable. I can also use the zero gravity position for sleeping which is really comfortable but sometimes difficult to get out of bed for any nightly trips the bathroom without looking for the remote and leveling the bed.

I do think it would be smart to talk to your doctor first if you have any underlying medical conditions. Here are a couple of articles that might be helpful:
-- Mayo Clinic Minute: What is the best sleeping position?:
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-what-is-the-best-sleeping-position/
-- What Are the Benefits of Elevating Your Legs?:
https://www.healthline.com/health/elevating-legs
Are you a side sleeper by nature?