If you fly with elytra into a nether portal while using fireworks, you get sent back to the overworld immediately after loading into the nether

Build a Hell Gate activation in the archive (you can load the terrain first, or not, but the waiting time will be longer.), fly into the Hell Gate with a scorpion (be sure to be in the fireworks acceleration state when entering, you can use fireworks all the time), and you will not be able to enter the Nether, but will return to the main world.