Hi PakNakal,
I switched your post to a new topic of its own so it wouldn’t get mixed in with posts from other members in a more general topic.
There is more about some of the newer “breed” of “one choice fits all” mattresses in post #3 here and a forum search on Leesa and on Casper and on Tuft Needle (you can just click the links) will bring up much more information and feedback about them.
There is also more about the 3 most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful quality/value comparisons between mattresses.
I would keep in mind that price alone is just one of the parts of the “value” of a mattress although the Tuft & Needle certainly uses high quality materials and there are no “weak links” in their design in terms of durability.
Leesa, Casper, and Tuft & Needle don’t have designs that have additional edge support but in most cases edge support isn’t necessary in a foam mattress (see post #33 here). Outside of designs that have specific edge support … the firmness of the support core and the thickness/softness of the comfort layers can both make a difference in how a mattress supports you when you sit on the edge of the mattress and with “roll together” when two people sleep in the middle of the mattress. Firmer mattresses will tend to have firmer edges as well.
I doubt that most of the forum members have specifically tried more than one of these mattresses and compared their edge support so you may need to use your own personal experience to decide whether the edge support of any of them is “good enough” for you. Of course if any of the members have personal experience with more than one of them then hopefully they will see your post and share their comments about how the edge support compares in the mattresses they have tried.
Dreamfoam is in a completely different category than any of the “one choice fits all” mattresses. They are a manufacturer with their own factory that actually makes their own mattresses and sells “factory direct” rather than a reseller so they have one less “layer” or “middle man” in their production chain which can sometimes lead to lower prices relative to the type and quality of the materials in a mattress. They also offer a very wide range of lower budget mattresses including latex/polyfoam hybrids, memory foam mattresses, polyfoam mattresses, and innerspring mattresses rather than only having a single choice so their mattresses will cater to a much wider range of customers. They also offer a range of firmness choices when you make a purchase and some of their mattresses are also component mattresses that allow you to change the firmness of your mattress after a purchase as well by exchanging a layer for a different firmness level if the initial choice you make doesn’t turn out as well as you hoped for.
How they compare with any of the “one choice fits all” types of mattresses would depend on the specifics of the mattresses you are comparing and the parts of your personal value equation that are most important to you.
I’m looking forward to finding out what you end up deciding 
Phoenix