If you have your simulation distance at 4 chunks as default hostile mobs can spawn very close to you, very often. Which makes the Nether almost impossible to survive in because of all the magma cubes and ghasts. However, making the default simulation distance 12 chunks could cause lag, even though it makes mobs spawn away from you. I know how to fix this. So, here is how to fix this. If your simulation distance is 4 chunks, not much mobs will spawn. If you simulation distance is 8 chunks, more mobs can spawn. You need to have a mob capacity for each simulation distance. And reduce the mob capacity for 4 chunks of simulation distance for the next update because the mob cap for 4 chunks of simulation distance right now is too high. Which makes it dangerous in the Nether. So much ghasts and magma cubes spawn and they're soo hard to defeat. If you do this, the Minecraft Nether in Bedrock edition will be just as easy to survive as it is on Java edition.