Unfortunately, anything to address the comfort issue is going to interfere with any seat heating or cooling systems if the vehicle has them installed.
But.... seating comfort in my view would take priority. One option is to go with a sheepskin seat cover.... as that can do a range of things from improving seat comfort as well as dealing with hot or cold seat issues pretty well. In my exeperience, simply having a good quality sheep skin seat cover under you can do wonders (this is what they use in commercial aircraft... though I am sure their seats are more comfortable for long duration anyway.
OR.. (and I know you already tried something along these lines) you could go with something like this which has a memory foam core: https://www.amazon.com/Domic-Cushio...hion+for+car&qid=1567115420&s=gateway&sr=8-19
Or for something even more robust underneath: https://www.amazon.com/Large-Cushio...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
Unfortunately... since everyone is different, you are destined to have to experiment with some trial and error.
But.... seating comfort in my view would take priority. One option is to go with a sheepskin seat cover.... as that can do a range of things from improving seat comfort as well as dealing with hot or cold seat issues pretty well. In my exeperience, simply having a good quality sheep skin seat cover under you can do wonders (this is what they use in commercial aircraft... though I am sure their seats are more comfortable for long duration anyway.
OR.. (and I know you already tried something along these lines) you could go with something like this which has a memory foam core: https://www.amazon.com/Domic-Cushio...hion+for+car&qid=1567115420&s=gateway&sr=8-19
Or for something even more robust underneath: https://www.amazon.com/Large-Cushio...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
Unfortunately... since everyone is different, you are destined to have to experiment with some trial and error.
