I just bought Minecraft Java, tested it and it worked for me:
You can see that the blocks are very pixelated from a distance, despite the best graphics quality in the game and yes I know that Mineraft is generally pixelated, but I find that much too exaggerated, it looks very muddy and uncomfortable.
MipMap level is set to 4?
Yes
You can change a lot in the graphics settings
simply settings → details → graphic settings
(if I'm not mistaken)
Yes, I have set everything to beautiful such as object distance to 500%
For me this is a normal screenshot, I see absolutely nothing unusual.
For real?