How to extrude inside mesh while keeping relative proportions from edges I can select the mesh letter I, extrude it on the X axis and scale it inward to create an edge around it.

When I do the same process with the mesh letter O, the result is this:


I would like to be able to create an identical inward edge that is inside the larger object, not only on the letter O but on any other mesh object.

How can I do this?

And how can I get rid of the face behind the newly extruded edge?

EDIT: I tried insetting but the mesh letter O looks like this:
Select all internal Edges and delete them.


Select whats left (two circles should left) and press Ctrl+E and choose Bridge Edge Loops.


Press I and Inset is working fine also you will have neat topology.