I had trouble with the #1 key on my rubber rollup keyboard and had to press really hard to get it to take the #1 key input and I have heard others complain about it, so I elected to try to fix it.
I peeled the two layers apart, this was a relatively simple thing to do, this exposes the back of the keys. I then cut a piece of aluminum foil to fit in the recess under the number one key, glued it in place with a thin layer of silicone, and let it cure. After it cured I put a thin layer of silicone on the original split seam between the top and bottom layers, let it cure and the keyboard is good as new again.

Just a FYI

I was going to order a new one but I figured they were all seconds to start with at that price, so the new one may be no better than the old one.

Being retired gives a guy time to do things like this Ha!