For single or region inset to an extent:
Step 1: extrude intended polygon(s) two levels
Step 2: perform an inward extrude (target polyloop) around the sides of your 1st extrusion made in Step 1
Step 3: perform an inset poly or region (whichever applies) on the originally selected polygon(s) from Step 1 as close as you can eyeball the same distance as the inward extrusion you performed in Step 2.
Step 4: qmesh (target polyloop) the outer ring of polygon(s) from the inset you just performed in Step 3 in the opposite direction of extrusions in step 1. if you are lucky you just trimmed off a ring of polygon(s)
Step 5: Select the remainder of the polygon(s) extruded in step 1 and qmesh Polygon(s) back towards the original surface until it snaps flush again.
here is a video demonstration of what I am talking about. Hackish and ugly and as you see in video not easy to actually match inset to extrusion, but it still works with an extra qmesh polyloop operation.
alternatively you can just perform steps 1 and 2, delete extruded polygon(s) and close the hole left behind if the geometry inside the inset doesn’t need to match, or in some cases you could bridge edges, but the 5 step method will work in many cases at least when relatively flat areas are being selected for the equidistant border inset.
Would save much time if you could check an option in the existing inset feature. If this feature ever does get added in an official manner… I would also suggest the option to have the inset snap if it’s about to deform from a perfect equidistant border.
if anyone wants to script the process to make it quicker… it’s experimental and not full proof, but go for it if you can streamline it, but please give me a copy of the script. Credit is always nice, but not necessary. mainly I just want to help if this ends up being useful for anyone else.