If a button has serious problem, it has to be replaced.

The usual, normal behavior of a metal contact switch is to bounce a few ms and then settle. That is why a 10ms debounce is most recommended. More may be better if you can spare the time, either in software or hardware.

In your case, with so many buttons, you will be using too many components. All these can be just fine be replaced with a few more lines of code for free. And with less posibility for a component or soldering it ot pcb to fail.

Ioannis