We had one on our Fifth Wheel. Had to constantly adjust the buckles on the straps. It stretched every time the wind got rough. Third season it gave up. The corners, on top had green growth each year under them. We padded the corners when we put it on.
Anyone who has wrestled one onto the top and deployed it knows how heavy it is.
A heavier version ,of the Sunbrella or whatever it is, might solve some problems.
They seem well designed but weather takes a quicker toll when it is exposed constantly ,for months, at a time.
Not sure how the stretching of the material could be solved. Probably can't. Just have to keep tightening them but not too snug.
Maybe parking it on the southeast or lee side, of a building, or tree line might help it.