Can I schedule a do not disturb for just one caller/contact ?

Hello Cglarocque,

Yes you can! However my personal advice, leave Do Not Disturb, to silent everyone not just one person. I'd create a different Focus mode to block out specific callers. Do Not Disturb should silent everyone and everything by default.

1. Open Settings
2. Tap Focus
3. Tap the plus icon in the top right
4. Tap Custom
5. Tap any icon and color combination you prefer and give it a name
6. Tap Next
7. Tap Customize Focus
8. Tap Choose People
9. Tap Silence Notifications From
10. Select the contact you'd like to silence all notifications for
11. Tap Next and follow onscreen instructions
12. Tap Done when finished
13. Scroll down to the bottom where it says Set A Schedule
14. Tap Add Schedule
15. You can select via Time, Location, or App
16. Select whatever meets your wants/needs and follow on screen instructions

Whenever you do that action selected the Focus mode will turn on silencing that one contact.

If you want to change Do Not Disturb,

1. Open Settings
2. Tap Focus
3. Tap People

From here you just set it up any way you'd like. If you need further assistance feel free to share a screenshot or ask another question and I'd be happy to keep assisting you.