Hi Pmo1,
What you need for a good nights sleep is what I call PPP which means good Posture and alignment, good Pressure relief, and a mattress that matches your Personal preferences. There is more about what each person “needs” in a mattress in post #4 here.
Post #1 here has all the basic information, steps, and guidelines you will need to make the most informed decisions and see through all the marketing “hype”. It will also help you with what to avoid completely which includes the major manufacturers such as Sealy or any other manufacturer that won’t tell you the type and quality of the materials inside their mattresses.
You can read more about gel materials in post #2 here and the other posts and information it links to.
Gel foams can be a legitimate choice as long as they are good quality/density and you aren’t buying them in the expectation that they are more effective than they really are. They can help a bit with temperature as you are going to sleep but once temperatures equalize the foams are an insulator and ongoing temperature regulation throughout the night depends on ventilation and moisture wicking (post #2 here has more about temperature regulation)
You’ve probably seen this but just in case you haven’t … the better options and possibilities I’m aware of in the Houston area (including Tesas Mattress Makers) are listed in post #2 here.
Phoenix