iCloud back up on iPhone and iPad suddenly drops in size

So For as long as I can remember my iphone back up has always sat around 10-11GB and my iPad around 5-6GB. I even had to increase my iCloud plan from 50 to 200GB and the Data stored was around 54Gb due to increase of photos etc.. Back in April this year i noticed all of a sudden it dropped and my iPhone back up went down to 6GB and iPad down to 900MB.. I also found an app called Beatwave in my settings menu and I had never heard of it and when I checked my purchases the app was not in the list of Apps I downloaded. I deleted the app from my menu in the fear it was some type of spyware. Also when enter my iCloud menu on phone and select back ups and it shows the list of all apps backed up I turned the Chinese keyboard off and deleted the data then when I scrolled back up the screen to where it says the next back up size it changed from 6 back to 10GB so I performed a back up and it still only backed up 6GB. It was as if the Data was being hidden or shadowed.. I decided to reset my device to factory and this didn’t help then about 2 months later both back ups returned to there original sizes.🤷🏻‍♂️ Now 3 months later the beat wave App has turned up in my iCloud back up list but is using another apps icon and no matter how many times I delete it it doesn’t go and both my back ups have just dropped in size again. Very long winded but any ideas?