A brand new shower bench

I just purchased a brand new shower bench as soon as I realized the old one was corroded. It came and nobody was as excited as I - you'd think I won a million dollars. I brought it home and set it up just as the old one was, higher on the left 2 legs than the ones on the inside- I huff and I puff and I take up to an hour! I assume it's cause of my surgery and I'm weaker so I continue to keep trying new configurations. Then after 4 transfers all differently I slide back and realize the surfaces, which used to be perfectly even, suddenly aren't- this is nuts. I figure out a final solution by folding a blanket to use as a platform but this should have ever been in the first place! Just like my latest wheelchair which 2 years later is still causing me to be stuck in dangerous situations. People who have never needed disability equipment make "mistakes" that none of their coworkers understand.