I am addressing a major bug that has been going on for awhile dealing with the Minecraft bedrock codebase realms. I among many others seem to be having an issue were extremely large worlds (In my case 4.1GB) overall seemingly anything over 3.7GB has extreme difficulty downloading or uploading worlds to realms. Along with crashing and half hour setbacks. 

When downloading the world it initializes the world fine then goes to a blank loading bar were the game stays perpetually.

When Uploading a large world it doesn't even make it that far. It goes through the original load bar then will freeze momentarily before saying either failed or going to an initializing upload screen that then stays like that forever. (I let my computer stay on that screen over night 10hrs and nothing). 

The limit for realms is said to be 5Gb but as of current anything larger than 3.3 to 3.7Gb eigther leads to crashing or endless load screens. It also is not an internet issue. Have tried using at multiple locations. This problem is the game or servers themselves.