Hi Sleepysteaks,
Without going into my usual long explanation of things with a lot of background and history.
It would seem you are on a tighter budget. @EngineeredSleep makes excellent mattresses. From their most basic to their more elaborate mattresses. Their customer service is excellent and reliable.
I am a huge advocate of mattress toppers. I do not subscribe to the idea of, if you are paying $$$ for a mattress, why does one need a topper. Many of the worlds most luxurious brands build their mattresses around their topper, with the expectation the topper will be added as part of the mattress system. I would not say that the ES Today’s mattress falls into the category of building a mattress around the topper, but it does fall into the category of, here you have a nicely built, firmer mattress, and if you want a bit more cushion or plushness along with additional mattress longevity, then add a topper.
The part that I differ is the type of topper you select. I have had a 3" memory foam topper in my mattress journey, and both my wife and I hated it. It was certainly conforming, but it was also, like a sinking quicksand hot lava surface.
If that is your thing, then by all means, select memory foam. Latex, latex alternative, wool in my opinion are better alternatives.
It is certainly not silly to plan your mattress system to include a topper, in fact, it is smart. Just do a little research on how memory foam feels, acts and reacts with your body and your mattress. Then compare it to latex, latex alternatives, or wool. I will tell you upfront, a decent wool topper will be double the cost of the mattress, but you will sleep cooler than on most other topper materials. If that is not a major important factor, then something like a titanflex topper (from brooklyn bedding) will keep your budget in mind and with it’s open cell technology, be very latex like in its response.
The Brooklyn Bedding SH is a very nice mattress as well. I have 3BB mattresses in my house). Yes they send a topper to soften it up, something you may want, if you do not order it with the pillowtop option, but keep in mind, they are not sending your their “best” topper either. It is usually a 2.5" basic memory foam topper.
In the spirit of the Brooklyn Bedding Signature Hybrid, another mattress choice in that range would be @Glacier, Glacier Sleep’s Original Mattress or their Summit model which adds a touch more foam, but considering you are looking at the Today’s mattress, the GS Original would likely be the option from their line-up. You may be less likely to need the topper, but I still like your thought process in having one.
Your thinking about how to approach this is fine. None of these mattresses will steer you wrong in quality, durability and longevity, but as you know that is only part of the equation. Comfort is critical.
Finally, no matter what mattress you choose, DO NOT SKIMP ON THE FOUNDATION. If you are considering a slatted foundation, the slats should be no more than 3" spaced, no less than 5/8 thick and 2-3" wide. Make sure there are center support legs on either the bed frame or the foundation support. You do not want those wooden slats to flex, they should be rigid, and stay away from the cheap Amazon metal bar foundations. This is an example of a foundation, that you would likely never need to buy another foundation again. While a bit more expensive, at the very least, you can use it as a benchmark to compare. You can learn about foundations here.
Lastly, whenever you move to a new mattress, particularly a firmer one then your previous mattress, be prepared to need new pillows, particularly as side sleepers. The pillow can make or break a comfortable pain free sleep. Pillows are mattresses for your head/neck. They should have structure, support and comfort. Here is my pillow collection as I am always looking for the holy grail of pillows. One pillow is not the answer, it is a start. Many folks need a couple or more pillows for different situations. Don’t be surprised that your pillow feels great for months, then something happens; you hurt your back, get a stuffy nose, or whatever, and the current pillow decides it does not want to feel comfortable and you need to temporary need to swap it out for a different one.
Hope this helps,
Maverick