As you probably know from the large number of forum posts here and on Reddit, many Roku remotes drain battery very rapidly. A pair of fresh batteries can be used up in 1--2 weeks. In short, my latest interaction with Roku strongly suggests that they knew this and that many of these issues are due to hardware issues that cannot be fixed by software updates. If you have been putting up with it, then you would be out of luck when you discover that this is a hardware issue and are out of warranty.
This happened to us with a brand new remote when we bought our first Roku stick in 2019. We have run through packs and packs of batteries of different brands. Because of this, we actually switched to Fire TV sticks. Only recently we tried to use it again with a new TV and got reminded of the severity of the battery drain again. This time, we Googled and found many posts and tried the recommended step to update remote to the latest version (Settings > System > System Restart). This didn't resolve the issue for us so I contacted support. I initially thought this was a firmware issue and wanted to see if there are more information we can try. But very quickly and confidently, the agent concluded this is due to hardware and asked me to "simply purchase a new remote".
I'm going to shelf our streaming stick again. Just wishing that there were a similar recall practice like with cars when the manufacture discovers hardware issues with brand new devices...
[EDIT] Here are some suggestions I have found from the web:
1) The streaming stick is powered off, causing the remote to continuously search for the stick. A possible solution is to power Roku with a dedicated power adapter, rather than the USB port from the TV that would be turned off with the TV. This is suggested by Roku employee (e.g., here, here)
2) Supposedly, Roku has released a software update to fix this issue (Settings > System > System Restart; see the replies by Roku employee here, here).
3) If the above fail, it is likely a hardware issue. You are lucky if you are under warranty (see this Reddit).
4) If you have been putting off this like us and are now out of warranty, you are out of luck (see an example response on this forum).
5) If you have a Roku TV, then the company will blame the TV manufacturers. TCL apparently received a lot of such complaints (see here).