How can I help my Belgian Malinois overcome her fear of the GPS fence collar so she'll roam my 2 acres freely without me present?

I have a 7 year old Belgian malinois, previously my primary PSA/ personal protection dog, whom I got at 7 months old. She was pick of the litter from an Ot Vitosha litter who had a few reactive bites before I got her. They resorted to e-collar corrections for fear of her reactivity. She has become one of the best dogs I’ve ever owned; high drive, great civil, high prey, more praise driven than anything. She is the dog that would kill herself trying to do what I ask. She had a complete fear of the ecollar, shutting down when I put it on her maybe 4 years ago. We worked through that and it’s a good tool to have at extremely low levels. I recently got a Dogtra GPS fence. She has resumed her shutdown with it, refusing to leave the carport unless I walk her despite me walking the perimeter with her with it on and playing fetch/tug with it on. The second I’m not with her she won’t leave the carport. What can I do? I have 2 acres I’d like her to be able to roam.