Hi fly19382!
I understand that you need to change the font in QuickBooks Online. Let me join this post so I can share some info and help you with it.
Currently, QuickBooks Online doesn't have a built-in option to modify its display setting. What we can suggest is to enhance the display features of your monitor.
Also, most browsers have an option to customize the font. This will affect the appearance of QuickBooks Online. Check your browser's settings and modify it from there.
Additionally, I recommend sending feedback to our developers and let them know that you need an option to modify the fonts. Simply go to the Gear icon and select Feedback.
With regard to your question if getting a new monitor will help, that would depend on its display features.
If you need references in managing a business, visit our help page: QBO Articles.
Do you have other concerns aside from the fonts? Comment them here so we can assist you.