After adding a Material Function Call node, I tried to select MF_UI_Scale from the dropdown menu, but it’s not listed. How can I access or enable it? [2025-06-04 19 49 13]

I just found them. They’re in the User Interface UEFN Project Template. If you create a project with that template, you’ll find both MF_UI_Scale and MF_UI_SDF_Circle, used in that tutorial. There are also a lot of cool UI things in the UI Material Lab you can download for ue5 from Fab.