update: including UniversalRP (URP) workaround at bottom!
Having this problem?
https://forum.unity.com/threads/gamma-colors-for-ui-and-linear-for-scene.529923/
Looking for a way to make only the UI matches to what is designed in Photoshop? Don’t want artists to change any workflow(possible solution for artists please refer to this comment) because you are in the middle of development? Try this.
Ming Wai Chan 