Beware when shopping for mattresses, store clerks will try to get you to commit by telling you false information. These 120-day return policies are a lie (unless it's Costco), of course they can deliver to your place in no time, there's no peak season, no. you don't sleep better in X and you don't need Y. They use all the sales tactic they can find (for example, if you're a couple they'll try to figure out who is the more opiniated of the two and side with them to force a buy).
In addition, all these brands are all owned by the same people. Tempur pedic, sealy, stearns, etc. There is no "luxury mattress". Past a certain price point (which I suspect is ~$500) it's all wasted money.
Don't trust the reviews! Nobody buys a mattress, sleep on it for a year or two, and then leaves a review on Reddit or on another website. It's all fake reviews. Any review that tells you X is bad, Y is much better, is basically fake. Don't trust what you read on reddit.
So what should you do? Costco or IKEA, that's it. Both have excellent mattresses and you don't need more.
My personal take is that you should avoid plushy beds, go for firm, and go for hybrid, because full memory foam tend to sink AND will be too hot during the summer.