1.21.4 64-bit Far Lands 5 (Nether)

First, the appearance of the Far Lands before generation was similar to the Overworld; the End was just islands. Then, upon reaching approximately 1 block on the same coordinates as the Overworld, the Far Lands appeared, but they weren't towering towards the ceiling. Unlike the Overworld, I went to overflowed locations like where cave_cheese would be, but there was no difference. Continuing like that, even after reaching the temperature (temperature distribution noise, 31Y), nothing changed. Around that point, pressing F3 showed a mess. Anyway, since I haven't found anything breaking further out than the temperature yet, I decided to go by directly inputting coordinates. Surprisingly, even up to 1000Y, there were no major issues or additional lag. Then, moving sequentially through coordinates beyond Y, like Gu, Gan, Jeong, and Jae, there was no change. Upon reaching 9-gok, I could see more gaps, and at 10-gok, they had almost disappeared. And I became the first person to place water in the Nether Far Lands. The lava ocean didn't break no matter how far I went; I couldn't go beyond it with commands.