Can you describe exactly how you are increasing font size? I have a 4k 27" monitor that I use in portrait mode for charts. I use Windows 10 Display settings to change "Scale and layout" to 125%. This makes everything larger, not just the fonts, so I do lose some screen real estate. I'd love to get more screen real estate while keeping fonts somewhat legible.
Settings/Ease of Access/Display... there's a slider to adjust text size in Windows. Most software allows user to adjust fonts within its own program.
Thanks! I used the particular app's settings so I could selectively increase fonts only on my 4k monitor, and not on the 2k and 1k monitors.