When I entered the Nether in the testing world i had made from the seed of my LAN world, it didn't generate and softlocked the game.

What I expected to happen was...:

I wanted to enter the nether to get the chest seeds of the chests in the bastion nearby to reset them in the main world since I want to reset all structure chests before making this world a server for my friends and I once 1.20 releases

What actually happened was...:

I was locked inside of a pitch black Nether, without any walls but with a ground (according to my X and  Z coordinates changing but not my Y coordinates when I walked with the F3 menu displayed) but I couldn't place torches on the floor. When, after restarting the game, I tried again, the same thing happened except I started falling when I entered the Nether.

I could open the inventory, and when I tried, no command seemed to work (tried /give, /kill, /tp and /gamemode).

When I tried to quit the game, it let me stuck for several minutes on the saving screen, until I closed Minecraft with the task manager (alt+F4 wouldn't work).