About two years ago I published a version of one of my apps as a beta testing version for a limited number of users, using the \"Beta\" version in Google Play Developer Cons
Just for information of anyone visiting this thread, here is what I did to stop beta appearing on my Google Play Store app listing.
At first, we launched with releases on beta track. Then, when the app was stable with enough feature set, we decided to go for full production. We decided to promote the latest beta release to production track (note we didn't place any apk/bundle on production track just promoted the beta release to production). Then we started to place every new release apk/bundle on production track and this gave us Superseded by production on beta track. But still we faced the issue of {App Name} (Beta) appearing in the application title on Google Play Store listing.
Then to remove this (Beta) from application title we had to go into Google Play Store App listing -> Release Management -> App Releases -> Beta Track -> Click on Manage Testers -> Click on Remove Testers. A confirmation dialog will open then click "Yes".
Removing the testers solved the problem.