video – The Xbox One S only displays 640×480 resolution when it can run in 720p (on the monitor)

I have my Xbox One S plugged into my monitor to play Fortnite (because I'm migrating from the controller (in addition to ps4 / switch) to the mouse / keyboard), but when it displays the screen, it remains stuck in 640×480. When I reconnect it to my TV, it works in 1080p or 720p. The adapter (HDMI to DVI / reverse) that I use supports it because I've used my Nintendo enabled switch (and the PS3). Here is what I tried. Enable YCC option and test "tv". Neither worked. I also unplugged and reconnected, but no. It's fine if it's not serviceable for the monitor, because I still have to get a new adapter (this one only has DVI, no audio output.)