CAN NOT DOWNLOAD CUSTOM WORLDS

THIS IS A MAJOR ISSUE THAT PRACTICALLY PREVENTS ME FROM PLAYING THE GAME. PLEASE READ. SHOULD THIS ISSUE BE CORRECTED I WILL TAKE DOWN THIS REVIEW. So I have Minecraft installed through the microsoft store, and I cannot get custom downloaded worlds and saves to work. Whenever I load one of the world, it just loads a small ocean seed and not the actual world itself. I suspect that this has something to do with the difference in files between the new version of Minecraft and the ones that come with the downloaded worlds. When I load downloaded worlds, they just take a seed of a recently played game world instead of actually loading the world that I downloaded. PLEASE FIX!!