Only a few Windowed resolutions?

I play all my games at 1600x900 resolution in Windowed mode because I have to monitor other things on my computer at the same time. However, when I switch to Windowed mode in Age of Empires 2 Definitive Edition there are only a few resolutions available and 1600x900 isn’t one of them. The highest it has listed is 1366x768 which is way too small.

What do I do?