This worked for me:
Edge Settings -> Appareance -> scroll down and search for Fonts and then:
Font size: Medium
Minimum font size: Medium
Standard font: Arial
Serif font: Arial
Sans-serif font: Arial
Fixed-width font: Arial
Then go to edge://flags/ -> Reset all -> Restart Edge
Then once again edge://flags/ -> Search for "New Pdf viewer" -> Disable -> Restart Edge
That should do it.