any recommendations on making your own foam mattress?
You usually have some kind of firm base, a middle layer, and a soft top layer. I went with a firm latex layer (44 ILD), a medium latex layer (30 ILD) [1], and a wool topper [2]. Very comfortable with good support, and a decent amount of bounce.
[1] https://sleeponlatex.com/products/natural-latex-mattress-top...