Did you restart your phone? If that still doesn't work, you can go to the 2 individual apps and turn the accessibility notifications off by selecting apps > notifications > notification categories. If the notification categories option isn't visible, go to notifications > advanced settings > tap the toggle > manage notification categories for each app.
These steps do not work nor apply individual apps have no accessibility notifications. My OP was done because the base "app" causing the notification is one called "Android System". So that is why I changed what I did based on a suggestion elsewhere on the web. And yes, have restarted the phone a number of times. So am still at square one yet. š
