This data pack allows you to start in the nether.
It gives you a little Spawning Cell with some Hyphae as the floor so you can make some tools.
It also has 2 dirt and 1 brown and 1 red mushroom, so you can make some food (combine dirt with grave to get course dirt and have all the dirt you want, mushrooms can only grow to big variants if on some kind of dirt)
You can change your default spawn by craft a Respawn Anchor with Grass(the one you need shears for not the block) for the Overworld, Chorus Flower for the End and Nether Wart for the Nether.

Crafting the blocks doesn't give you them it will immediately remove how ever many you crafted, but won't take and you already had.
You can craft them in stacks so don't shift click or all you Respawn Anchors are gone but at least your World Spawn is changed.

The pack doesn't seem to auto load at the moment and have to do /reload to make it work, once its started all seems to work fine.

Hope everyone has fun.
It should work for multi player but I haven't tested that part, however all the commands are setup for it.

There is a little bit of spawn protection I added using Moving Pistons so that respawning doesn't mess up (basically you just cant build on top of the bedrock at the spawn points.