Worst mattress I've owned

Worst mattress ever. The Alpine HDM mattress seemed comfortable when laying on it in the showroom. After returning twice and researching the components, comparing with other mattresses, all seemed promising and decent for the environment. After purchase, it took over a month for the bed to arrive (tail end of the pandemic) and it was the wrong firmness. These mattresses unzip to reveal the different layers, including, for this mattress, a bottom layer of small coils. After another month passed, they simply opened the bed and swapped out a layer of foam, that was it. No improvement. And because it's a short warranty and it took a lot of time for things to arrive, by the time I realized that the mattress was not going to improve (even with two of us sleeping on it occasionally, which we hoped would help it settle in), it was out of warranty. These mattresses supposedly don't require a box spring, which we were looking for, but definitely feels like it needs one, though not sure even that would improve it. Terrible support, whether for a single petite person, or with the addition of a tall, heavier person. Absolutely avoid. We purchased a Purple bed for our son, and he loves it. But I'm going back to a more traditional mattress ~ those have held up for years and have provided more consistent support. Hoped to find something more eco and allergy-friendly, which these mattresses supposedly are, but this was definitely not the answer. A waste of a lot of money ($2,000 with delivery and other fees) and the cause of neck and back pain/problems that mysteriously disappear when sleeping on different mattresses while traveling.