Desktop App is blurry

@Karol Buratynski - The first step I would suggest taking is to reset the application data - steps can be found in this article:

https://help.miro.com/hc/en-us/articles/360017572854-Desktop-app

If that doesn't resolve your issue, please tell us more about your setup, e.g., OS and version, laptop or external monitor, screen resolution (with scaling applied?).