5'10" 240lbs
I had a no-name memory foam mattress from Woot.com for about 4 years. I built a platform for it instead of using slats or a boxspring. Any mattress is better supported and will work as designed with a platform over any other base support. Go this route. It doesn't have to be fancy, even laying 3/8+" plywood over your existing supports will make a difference in your existing mattress.
Last year I retired the memory foam to the guest room. When not used daily it's nice and supportive, though somewhat warm. Used daily it never really returned to a flat square shape, hence over time became less and less supportive. I gave up on the quicksand feeling trying to turn over in bed or conduct other pleasure activities.
I considered many different replacements, eventually settling on a hybrid mattress. Having springs to provide support, but a giving memory foam top absolutely helped. But in the end I gave up on the memory foam because of the heat issue, I like to sleep cool. I went with
Nest Bedding's Latex Hybrid Mattress. While more expensive than other online purchase options, the latex is both cooler and more resilient than memory foam. I also liked that you can change out the latex layer in halves if you need to change firmness, so you don't need a whole new mattress if you happen to change partners or become long term injured and need something softer/firmer. Going on more than a year now, and I still love the mattress. I'm comfortable enough in bed that I often don't want to leave it. Rolling over and going back to sleep has become a frequent occurrence, even if I've already managed 8 hours! I've only rotated the mattress once, because I sadly sleep alone 99% of the time and wanted to start breaking in the other side. The mattress does have some bounce to it because of the springs, but they are encapsulated so most of it does not transfer. (You won't see the jumping on the bed with red wine on the other corner with this mattress). But my partners have never complained about feeling my shifting in the night, even when specifically asked.
For something you're supposed to spend 1/3 of every single day on (unless you frequently travel), spend some money and get what works for you. Find reviews from people with your build and body weight. Sadly many of the online reviews that you can find are these skinny-jean millennials who don't have any mass to them. So they tend to slam the firm mattress as too firm and uncomfortable, when in reality it's just what someone of normal or large proportions needs.