The right button on the directional pad stopped working recently. If I press down very hard on it, it will sometimes work. I have tried resetting the Chromecast and this didn't resolve the issue. Is it possible to get a replacement remote?
That sounds like a hardware issue in your remote.
If you're still under warranty, you can get a replacement.
I use the Virtual Remote 90% of the time now.
Or, depending on your country, you can buy a new one
Also, if you have a compatible Android device, you can use a Virtual Remote on your phone or tablet. That will save a lot of wear-and-tear on your physical remote.