What happens when you go to Preferences > File Handling > Recent File List Contains ... and reduce the number to 12 or 10?
A couple of things to check:
1. Does your screen meet the minimum requirements for size?
2. If your screen does meet those requirements, have you set a scale in Windows 10? (Windows >Settings > System > Display >Scale and Layout) which increases the size of the user interface elements but by doing so reduces the number of pixels which can used by the interface, so some dialogues may not fit?