This app was mentioned in 10 comments, with an average of 1.80 upvotes
https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free&hl=en
This app should work to stop the ads from turning on the sound forcefully. Make sure to set up all of the volume options to zero, and then click on the lock so the volume is locked, which doesn't let Yoolotto change the volume.
Hope this helps!
EDIT: You do not need root to use this app! I personally think this is the easiest way to turn off the sound permanently.
Install the app, set to silent or manner mode. Then lock the volume controls. This should keep the app from making noise when it plays ads. I still appear to be earning even though the ads are muted.
YooLotto will still send push notifications, go to settings, apps, then uncheck the show notifications options. This will prevent your farm from vibrating every time you get a point. Ads seem to be in good supply this afternoon. I am running 4xLG Sunrise and a Moto E 2nd Gen.
Try Vollynx. It has an option to "lock" your volume, e.g. if your phone is set to silent and then you press volume up, normally it will change to vibrate mode. But this app makes sure that it will stay on silent mode.
Or, if you're on ringer mode and it's set to, say, 2/15 loudness, pressing volume up will not increase the ringer volume (but you'll still be able to pull down the volume tray)
Volume Locker was suggested to me in this subreddit, and it works at keeping the volume locked at what you set it at, and it does not require root.
https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free&hl=en
Would an app like this work?: https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free
Try this one perhaps https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free
Perhaps try an app like this https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free
This might fit your needs...
https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free&hl=en
Apparently this works: https://play.google.com/store/apps/details?id=com.loadlynx_jp.vollynx.free&hl=en. I haven't tested it yet but I will after work.