Hangouts, Google Voice, and "SMS is no longer supported" notification on a WiFi-only tablet

Although I have been a long-time user of Google Voice and Hangouts, I only recently got my first Android tablet (WiFi only, no cellular). The way the first two interact with the tablet is puzzling and frustrating: - As far as I can tell, Hangouts is the tool that Google wants us to use for Google Voice SMS messages. - It seems that recently Google removed SMS support from Hangouts except for Google Voice SMS that is still supported, and provided a way to choose what app to use as the main SMS app. - With Hangouts installed, everything seems to work, but I get constantly spammed by a Hangouts notification saying that SMS is no longer supported. I have found no way to silence this notification unless I disable all Hangouts notifications, which would make me miss other Hangouts IMs. - In the attempt to silence the SMS is no longer supported spam notifications, I tried to install other SMS apps, but since my tablet is WiFi only, I am unable to install them. - I only found one SMS app that would install without the cellular hardware (I think called Messenger) and it spammed me with so many advertising notifications that I had to uninstall it, the cure was worse than the illness. How to silence the Hangouts' "SMS is no longer supported" notification? Otherwise, how to install another SMS app on a WiFi-only tablet that stays nice and silent (which is ideal as I probably will never use it, I would only install it to silence the Hangouts notification)?