Can you give more details?
This is an age-old issue: Higher resolutions are crisper/sharper....but smaller. Lower resolutions make everything on screen bigger, but they get fuzzy/less sharp. Some monitors only really look good at native resolution, which is typically the highest (smallest) resolution.
Many applications let you zoom in. Hopefully, you are aware...many browsers for example, you can hold down
Command and
+ to zoom in (
Command and
- to zoom out). does Notes have a zoom feature?
Have you ever considered retiring Notes for something from the current century?
Yes, generally larger monitors at a similar resolution will make everything, well, larger. But depending on resolution, you may not find a substantial improvement. You might want to check and compare if you have an Apple store near by.
You can also change the default font size in the Finder, which helps while navigating, but not in apps.