I found that on my phone, I went to the sounds and vibrations section and clicked on vibration intensity. It gave me the choice to completely lower the vibrations for notifications but I could keep the phone vibration intensity up
My default Messages app suddenly stopped opening texts. (could write them though and only had about 50 txt messages in total). Oppo phone android software didn't give 'clear cache' option for Messages. However, found an app on my phone called Messenger. Once this was disabled, Messages app worked again (no reboot necessary)
On my LG K92 and Lenovo Duet (Chromebook), I had to search for "special app access". Then choose "usage access" and you'll be taken to a list of apps. Choose your app and change settings appropriately.