I have a PC with Windows 10. I was using the version 2022.07.2 and an update pop-up to 2022.12.0 showed up, so I decided to install it. After installing it, all the IDE window began to become blurry, and I couldn't urderstand anything else. So I installed the previous version again and this problem has been vanished.
The effect in the attached image is not from the print resolution. This is exactly how the IDE looked like on my screen, unlike all the other programs that were running at the same time.
Have you tried changing to software rendering?, you can change it by holding the Ctrl key while opening RStudio, then you should see this menu and change the "Rendering Engine" to "Software".