Question Where to find high resolution manga.

[Shinsakuto]

Hi everyone. My problem is that I can only find manga scans with height of 1080. which is the height of a Full HD display. But i have my screen in portrait mode so I am going 1080x1920 which is awesome to read manga, but then i have to scale the scans to nearly twice their size which is a huge quality loss. So I'm basically looking for any method to acquire manga scans with a height of 1920 or more. Thank you beforehand.

Have a nice day, Shinsakuto.