Did you know that Shader Graphs were not supported in the UI in 2022?
This video presents a workaround to get over that roadblock

Think Unity should update this? Here's a Unity issue that seems relevant (although I'm not entirely sure they understand how simple this request actually is):
https://issuetracker.unity3d.com/issu...

Update: This feature was addressed in 2023:
Nuilescent says:
Should add a note in the description pointing to the new UGUI Canvas shader! Version 2023.2 and up features a brand new shader specifically for UI. And it supports masking too!