Display settings only show up to 1080p for a 4k monitor

I am using a 4k monitor. But when I go to scaling options, it doesn't show 3840 x 2160. BetterDisplay app does the same thing, max resolution is 1080p Can you guys help me? Thanks :) https://preview.redd.it/jf7zi507zjie1.png?width=493&format=png&auto=webp&s=d50c3e8312b0bee68477d04373b9fba55b36d933