Welcome to the Mattress Underground!
I think you hit the nail on the head here:
I mistakenly confused the need for pressure relief for a need for a softer mattress.
So many people do this - and I used to as well. Living with a spouse who has a bad back has taught me that sometimes more support is better.
You have identified that you want to be ‘on’ the mattress not ‘in’ the mattress - so you would like the ‘pushback’ that you get from coils.
One mattress made by a reputable company that you may like is the Naturepedic EOS mattress. It is a hybrid, and you can customize both the support layer (which is coils) and the cushioning layer of latex to meet your needs. There are five different firmness configurations. A queen size comes in at under 3K right now with the Memorial Day sale going on.
If you need to tweak it after buying, you have 90 days to swap out layers. Or - if you wish you can add a topper, which also helps prevent the impressions you were talking about.
I agree with both BillyIdol and Maverick - there is some maintenance required with even a higher-end mattress, particularly when you first get it. Rotating and flipping components or the whole mattress really help.
There are some other options on our site also - The EOS comes in a pillowtop version as well (although it may be more cushioning than you would like). We do have some all latex mattresses that can be customized to be more on the firm side also. The Laurel by Healthy Choice would come in at under $3,400 now on sale, for example.
Good luck with your search! We’re here to help if you need it.