1. Go to end (e.g. /setblock ~ ~ ~ end_portal)
2. Place nether portal and go through (e.g. /setblock ~ ~ ~ portal)

Result: You can walk around and collide with blocks, also the biome appears in F3, but you can't see the blocks. It's like when chunks don't fully load because of lag, but everywhere.

Similar to MC-7169, but in current versions and the world does open, it's just invisible.