Accessing Channels without having to scroll through 300 channels...

Maybe try adding a DVR box (you can get one for ~$50+) that comes with its own remote?  You would connect your antenna to the DVR box, then connect your DVR box via HDMI or RCA cables to your TV input port.  Then you setup the DVR as a new input on the main app screen of your Roku, instead of using the default live TV option. This would allow you to regain a lot of control by using the DVR remote.  I have something like this setup and it works well.