I added a cylinder with Depth of 0.1m
Tn edit mode tab I selected top and bottom faces.
I used bevel tool Ctrl+B to bevel (with 16 segments) for 0.05m. In the bottom left of the viewport there is a window that allows you to type values by keyboard. If you left click anywhere after beveling it will disappear!
This shows curvature of this disk compared to 64 segment circle with radius of 0.05m.
Thanks to @Jachym Michal for this tip.
We accidentally created some duplicated vertices and edges in the very middle. They might cause problems with rendering. It's very easy to remove them. When we are in edit mode we select everything with A and then press Alt+M and chose
By Distance from merge menu. You should not see any change, but duplicated vertices are gone!