Going to nether worked in 1.20.4, but when I upgraded my world to 1.20.5, it stopped working. I went to nether portal and waited long time. At screen there was purple nether portal texture, hotbar and + in the center of screen. I stopped trying and went out from nether portal. A little later, "Loading terrain" came to my screen and then game crashed. I tried it many times with the same results (different days, computer shutted down between)

I'm playing vanilla Minecraft without mods or resource packs. (I started world with 1.20.4 and upgraded it 1.20.5 when it released)