I would put in an extensive mine field, and do it under the DoD budget as a legitimate military cost. Put a road on our side with very frequent patrols - ground and air. That border should be shut tight. Weapons live. We did this kind of border with North Korea and we dealt with it in Germany - it is not that hard.
DJT would have to declare it an invasion first (which it is). The invoke the Defense Authorization Act of 2006 (I think that’s the one) which gives him power during an invasion to militarize the border - live fire then OK.
Two fences, separated by 200 yards. Anyone between the fences liable to be shot on sight. Patrol with drones. Put signs in 12 languages explaining the conditions.
Sure don’t see many crossing the DMZ do you?
I know that is a wild fantasy of yours, but obviously that will never happen.