Roku menu path Settings/System/About will show you your Roku model and model number. It's a good idea to report these when asking questions because different models have different features and capabilities. If we know the model you can get better targeted suggestions.
If the problem continues with the batteries out of the remote, then it exists within the Roku itself.
Did your "unplugging and replugging everything" include the power cord to the Roku?
These things are just special purpose computers. Like their big brothers sometimes clearing things out by restarting them can correct problems. (Note that if yours is a Roku TV with "Fast start" enabled, turning it off and back on just puts it into and out of a standby state and does NOT give you a complete restart.)
Depending on your Roku model and Roku version number you'll find the System restart option under Settings > System > Power or if not there, under Settings > System
If a restart doesn't do it, or if you don't have sufficient control with the remote to navigate the Roku menus, you can also restart by pulling the power plug to the Roku for a few seconds then plugging it back in and wait for it to restart.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X