Make sure you are not opening a duplicate.

• I have searched the issue tracker and did not find an issue describing my bug.

Description of your suggestion.

When you go through the Void Portal to return to the overworld, if the overworld has a world border, it spawns you outside of it and thus kills you instantly. I believe the teleport return should take into account the world border and thus spawn the player at the largest coordinate possible within the world border.

Example:
World border is set to 10k on each side.

In the end you are at at X:12500, Y:457. When you TP back, it should limit X to 10,000 and keep Y at 457 because 457 isn't beyond the 10k world border limit.