I have two Roku Express 4k+ units that seem to be failing frequently, requiring a power restart to continue properly playing back video & audio content; but also other issues such as losing remote functionality. The frequency with which you have restart the unit was initially very low (days to weeks) but now has reached multiple times daily on both units. Both are less than a year old.
Most frequently either the audio content stops and will not come back until the unit is reset or the video resolution degrades to the point of being difficult to watch. Checking my internet speed reliably shows >500 mbps (I have Xfinity 1 Gig service) and restarting the device almost always resolves the issue; but its annoying when it must be done multiple times daily (basically after every hour or two of playback). Everything is fine again after reset for a short while.
Most recently, the units have started also making an annoying, faint, high pitched "chirping sound" which goes on continuously for several seconds to a minute. This occurs off and on whether the units are streaming or not. I'd estimate 30-40% of the time it's making the annoying chirping sound.
If it were a single unit I'd think ok, maybe I just got a bad one; but the same thing is happening on two units purchased several months apart; both from Amazon. Right now I can think of nothing else to do but throw the units away and re-purchase video streaming devices from another manufacturer. Is this normal for a Roku Express 4K+? Are they typically a "throw away" device after 6-12 months?