These dedicated buttons are a pain and I wish the greedy practice of putting them there would never have been started. I have multiple streaming devices and they all have these shortcut buttons. At least the Cromecast TV only has two and their buttons are recessed and don't raise above the surface. Although I don't like having the buttons there.. at least I have never accidentally bumped them on that remote and interrupted what I was watching.
To me, the best approach to disabling these buttons would be to make a very thin cover that could slip over that section of the remote, and prevent the buttons from being activated. It doesn't harm the remote, you don't have to crack the case open, and can be taken off if you change your mind. If I had a vacuum form machine I could come up with a cover in about 10 mins. It seems so simple.
If you made the covers thin enough they would still allow the use of the silicone remote covers.
Heck even a thick rubber sticker cut out to fit around the buttons would be better than nothing.
The Sideclick people should come out with an accessory to do that since they already have slip-on plastic adapters that are perfectly fitted to the different remotes. Sideclick are you possibly reading this?