I have a similar situation to the OP. My large back deck has a Behr product on it now that was supposed to be elastomeric, that is, it was supposed to last several years. Two years later and I need to re-do it, probably with a different product. It's just flaky flaky flaky. Very disappointing. I hired someone to do it, which may have been my mistake.
Five years ago I did my medium-sized front porch with Rust-Oleum Concrete and Deck Restore. It's hard to overstate how important surface prep is when using one of these products, and following all the directions closely. Mine has performed brilliantly. I was meticulous during prep and application. I had an advantage in that the front porch didn't have a stain on it previously -- the wood was just weathered. Therefore I didn't need to remove old stain first. On my back deck, I anticipate needing to pressure wash and then probably use a stripper as well to get the old product off. I do think I'll go with the Rust-Oleum Concrete and Deck Restore product though, because I've had a good experience with it. I have a few misgivings as I've seen a lot of videos and complaints online that show the product flaking off terribly. But aside from a few spots on the leading edges of the front porch stairs that are very high traffic and can easily be touched up, I have had no flaking at all in five years.