The key is the force which would in turn need the mass of the dragon to be within range of an average Isekai Truck. The omniscient narrator said that exact thing in the strip that introduced the concept. Even then it seems to be a coinflip.
Sadly there's probably zero way for MC or Isekai Giant here to find out what the correct force range is but if that could somehow be determined she could probably send him home in ONEPUNCH after some practice.
On another note, an effective way to defeat an invincible demon lord in an Isekai world is to Isekai HIM to the real world. Not sure why shepherd felt the need to specify that the giant is an original species tho. Cat Ghost Cleric and the Dinorabbits are definitely not stereotypical either.