Samsung
Change Font Size auf Samsung
Text that looks too small on a Samsung phone is usually a system setting, not a display defect. Samsung's One UI ships with a compact default font size that keeps more content visible on screen, which can strain your eyes if you are used to larger text.
You can adjust this directly from the display menu. Go to Settings ➔ Display ➔ Font size and style, then Swipe left or right to set the Font size. The change applies immediately across menus, notifications, and most apps that rely on the system font.
This setting only changes the size of text. App icons, widgets, and other on-screen elements keep their original size. If you also want everything on screen to appear larger, look for the separate Screen zoom option inside the same Display menu.
If some apps still show tiny text after adjusting this slider, they likely draw their own interface instead of using the system font. In that case, check whether the app itself has a text size option in its own settings.