I am on my 3rd remote for the same Stick Plus. They just die for no reason. Literally one minute they work, you put it down and moments later you pick it up and NOTHING!!! I press the buttons and no response, I change the batteries and no response, I unplug the stick from the TV and nothing, I try to reset the remote and nothing.
An entire generation of these garbage remotes and money wasted replacing them. And now apparently I cannot replace it because the only remotes Roku now sells are not compatible with my device! So now I have to waste more money buying a whole new Roku device.
The current voice remotes from Roku will work on your Stick plus, only the $14.99 simple remote won't. It might be the long-range wireless receiver, the bump in the usb cable that going out instead of the remotes? The wifi remote and internet both communicate with usb cable directly instead of the stick plus.
Roku seems to have these back in stock:
USB Power Cable with Long-range Wi-Fi® Receiver | Roku
I've been lucky and haven't had any remote issues (knock on wood), but this is one reason I avoid the sticks. If your remote dies you're beholden to Roku to get a new one. With the other devices you can get a cheap universal remote and you're back in business.
Although it wouldn't be an option for me (since I think it's stupid), you can always use the Roku app on your phone/tablet as a remote.
The current voice remotes from Roku will work on your Stick plus, only the $14.99 simple remote won't. It might be the long-range wireless receiver, the bump in the usb cable that going out instead of the remotes? The wifi remote and internet both communicate with usb cable directly instead of the stick plus.
Roku seems to have these back in stock:
USB Power Cable with Long-range Wi-Fi® Receiver | Roku
I hate using the app. I just bought a new Ultra, even though I hate the idea of the rechargeable remote. But I went with the Ultra because like you said I can buy a universal aftermarket remote if I have to. The Stick is the only model that there is no universal for.