As the title says, any image gets blurry after 33% zoom.
Go into preferences and change Screen Scaling to 100% and UI Scaling to 200%. This will make the first zoom steps a bit less drastic.
However you will always lose image information below 100% zoom. Pixels are the smallest component of what can be displayed on a monitor, so 100% is showing 100% of the image, and any lower than that has to remove pixels to zoom it out.
You can switch to the old render engine in Preferences -> Experimental, which makes it simply remove pixels when zoomed below 100% instead of interpolating (blurring) them, but like I said, still the same loss of information.