[Rey_a]

Not that easy to answer this ...

My eyesight is also ageing, and when playing music, I use a pair of glasses that I had made especially for the distance my eyes are away from the computer screen while playing. This helps quite a bit and would be the first thing I would recommend.

Apart from that, increasing the size of the score (by using a bigger screen or other means) is indeed also likely to help. You can easily simulate this yourself by zooming in a bit on your current screen to a size that the score would be on the 27 inch screen.

Increasing the resolution from 1080 to 1440 will not help things in my opinion. This would only make a difference for people with good eyesight who see the edges of the image rasorsharp.  If you see it (a bit) blurred, then 1080 to 1440 will probably not make a difference.

The resolution at which the scores were scanned also has an effect, of course.

Succes!

Rudy