A framing escape from the school of thought that says: don't fight the grip, dismantle the structure that gives the grip its power.
Break a two-hand collar grab and create the distance for a decisive counter.
A two-hand collar grab shortens your air and delivers you to the wall. Do not try to pry the hands off. Build a frame instead.
Bring both forearms up between their arms and post the blades of your wrists under their chin. Bone against bone uses their own downward pressure to load their neck.
Circle your hips off their line. The frame drives their chin up and back until their spine breaks alignment, then return with a straight palm, knee, or shove to create distance.