Yes but you could lose a great deal of volume.
Depending on your soil you could perhaps have a ten foot fence with 4 feet of the fence buried below ground to provide stability. It could save on concrete and increase your storage volume at the same time.
not saying a pyrimid shape just a wider base and skinnier top could help stability butwould result in less water pressure But youre not going to get much pressure at 4/10’s pounds per verticle foot
Stainless ? who can afford thatstuff any more
polly is good see H.D.P.E products used extensively in construction