It really sounds as if the keyboard has got bent, this is exactly what happened to me. Using it on anything other than a rock solid flat surface is going to cause it to bend even slightly, and this includes lap typing.
I don’t think this product was ever meant to be used exclusively, it’s a cover 1st that just happens to include a keyboard, and is a very clever but ultimately not a very robust design if not used under exactly the correct conditions.
Just buy an Apple smart keyboard. It will outlast the iPad and is not model dependent so when Apple change the iPad design just because they can you can port it to the new device nil cost.