Hi Antilokhos,
You can see some of my thoughts about airbeds in this article. I would also keep in mind that that there are different types of softness/firmness (see post #15 here) and when you adjust the firmness of the air bladder in an airbed you are mainly adjusting the support of the mattress … not the comfort layers of the mattress … and the softer the setting the more likely that you will experience sagging under the heavier parts of your body (generally hips/pelvis) which can compromise alignment.
There is more about the variables that can affect sleeping temperature in post #2 here that can help you choose a mattress that uses more temperature regulating components and materials so you are less likely to sleep hot.
Post #3 here and the posts it links to have more information about choosing a more suitable and durable mattress for those that are in higher weight ranges and should be helpful.
There are also some foam density guidelines in post #4 here and more detailed information about the many variables that can affect the durability and useful life of a mattress relative to each person in post #4 here and the posts it links to.
Phoenix