Hi rytiedye,
Welcome to the Mattress Forum! 
That’s quite a bit of reading!
I’m not sure what you mean by “not rejuvenating”, but I’m guessing that you still would prefer a bit more surface comfort for sleeping upon your side.
As the memory foam topper assisted with your comfort, that of course leans in the direction of you desiring a bit more surface plushness on top of your current mattress, confirming my earlier thoughts.
Memory foam will tend to be the least breathable of the most common foam materials. With the gel infused into your memory foam topper, gel foams will tend to have a temporary effect on temperature while you are first going to sleep until temperatures equalize but have less effect on temperature regulation throughout the course of the night. You can read more about phase change materials in post #9 here and at the end of post #4 here) and you can read more about the various different types of gel foams in post #2 here.
Regarding the color showing through your sheets, I would strongly recommend that you protect your topper with a zippered encasement, even if it’s a basic one from a department or linen store. Right now, your topper should be covered at a minimum by your mattress pad/protector and your fitted sheet.
Sleeping on your side comfortably can be achieved with traditional innerspring or “foam (polyfoam, memory foam, latex, or a combination of thereof). It just comes down to finding the combinations that you prefer. If you decide to keep your mattress but wish to try a latex topper that you can return, you may wish to take a look at site member MattressTopper.com. They offer 3” Talalay toppers in three different firmnesses, and the Talalay will be more breathable than your current memory foam topper.
Regarding Purple, a forum search on Purple will also bring up much more information and feedback about them as well. They are using a layer of buckling column gel which is a good quality and durable material. There is more about buckling column gel in this article and in post #2 here and the posts it links to and a forum search on " buckling column gel " (you can just click the link) will also bring up more comments and feedback about it as well. The buckling column gel is 2" thick and then there is a 3.25" layer of 1.8 lb polyfoam under the buckling column gel (this may be 3.5" thick because they list two different thicknesses in their FAQ and the description for each size) and a 4" 2.0 lb polyfoam base layer which are both good quality materials so there are no lower quality materials or weak links in the mattress that would compromise the durability or useful life of the mattress although I would add a caution for those that are in higher weight ranges (mid 200’s or higher) because of the 1.8 lb polyfoam comfort layer.
As you should already be aware, choosing a product based upon advertising and/or reviews would generally be the least reliable way to select a mattress (see post #13 here). I can assist with the “how” to choose a mattress, but I can’t select a mattress for you or make specific recommendations, as there are too many unknowns, variables and personal preferences involved to do so with any accuracy. If you do decide to select a new mattress, I would be sure that you start your process with a review of the Mattress Shopping Tutorial and the steps listed within that will help you select a mattress.
Let me know what you decide to do!
Phoenix