Blocks Break But It Disappears Or If You Place anything it Disapears Stuck on Save and exit after the bug

I am on Minecraft Bedrock Edition 1.12.0. When I start a new world and play for a while the game tends to bug out when I try to break blocks. When I try to break blocks it disappears and I cant pick it up. Also, when I place items down and try to pick it up, it disappears and you don't see the breaking animations. You cant hear the sound when you open doors or when you break blocks or any object. A final thing, to solve this I tried to save and exit and it's been stuck on that for hours. Every time I quit when it is stuck on "The game is being saved. Please do not turn off your device" I lose all my progress because it didn't save. Please try to fix this because it would be a waste of my money to get the game and this keeps happening. The game runs fast no lag. Maybe if you guys add a manual save to the game it would be better because when the bug happens we could save it then quit and reopen. I had this problem in version 1.11 too. Please fix this!