Dimension teleportation is broken

Hi, a few months ago I created a realm and the world file size increased to 3gb. I downloaded the map after 1.16 released, it started off with no issues until it reached 3.5gb. Everytime I go inside the portal and meanwhile it transfer me into the dimension, it crashed. When I join back the map got rolled back, it's also sometimes when the world itself creating roll backs that it was creating more bugs and glitches, there is a video and an image of the crash. Although they're not the same case, but this happens alot on the world.