The other thing you may want to try is to let the user decide at what scale the user wants to render in your game, one thing that may not seem intuitive is that if you have 4k in a big monitor close to your face even if your text is small it is readable and seems ok, while if you have 4k screen in a mobile phone it won’t be legible at all.
For some young players a small font will be ok, while for older players will not, and bigger font will be better.