The bug can no longer be done in this way but only because Vibrant Visuals is forced off, regardless of the active packs in the world. I’m not sure if this is still an issue if vibrant visuals were available though.
I found this report when checking on another bug (MCPE-227984 ) where I left a comment. In summary though, blurriness is a part of TAA/TAAU that can be seen in all games where it’s used.
I don’t think this is a bug with Minecraft. TAAU/TAA, or Temporal Anti-Aliasing, is used in a lot of games and blurriness is a known side effect of its use. So Minecraft’s TAA is working properly, it just has a blurry output because that’s how TAA works. You could switch to bilinear upscaling instead, but the output may be quite jagged.
I’ve also updated to Windows 11 25H2 10.0.26200 N/A Build 26200, with Nvidia driver 581.57.0