A knee pillow. I have always struggled with the occasional back pain because I would sometimes twist my legs/back at night and be in pain the next day(s). A knee pillow has massively changed that for me. I pretty much never have issues with my back caused by sleeping weird now.
In a similar vein, nasal strips. My nose often gets obstructed at night and it caused a ton of sleepless nights because I had a hard time breathing. Finding the strong nasal strips I'm now using pretty much eliminated that problem.
I was in your boat, and the strips just dont cut it for me.
I bought a cheap pack of "nasal dialators" on amazon (tried a variety pack first to find the size that worked best, now settled on 'large'). They're basically plastic cones that force your nostrils open. They hurt a little at first, but now im used to them and breathe SO MUCH better.
I tried many from Amazon, best was one called Airmax, but irritated with regular usage. I've since found "Noson.ch" and their design is fantastic. You have to buy direct from Switzerland and it's expensive, but personally it's worth it for a better nights sleep.
I've been using the Breathe Right "Extra Strength" ones. They are the only ones that have reliably stayed stuck to my skin overnight and strong enough to keep my nose open.