I have a 4k image that has text, in CSS is set to 90vh and 90vw (high and width), but in the page looks blurred, and when I zoom instead of losing quality it gets upgraded, how do I make it always have the full quality of the image?
I have already tried to use image-resolution and image-rendering properties but didn't work
If it's a 4k image, it will remain a 4k image.
This is almost positively a result your eyes playing a trick.
There could certainly be distortion, however, if the image is being manipulated by anything else in the code, like CSS or JS.