Major separation anxiety resurfacing

Hey everyone, my dog Kiwi (6F) and I recently moved to hawaii. She just turned 6 last week, and I've had her since she was just over a year old. She had quite a large neglect history before I got her (given up by 4 different owners in her first year of life, the last of which was a frequent drug user and would couch hop from place to place while leaving Kiwi in the car for double-digit hours a day.

Since I've had her, we've moved and driven all around the US. She is a great travel dog and generally very secure.. we've come a long way from her prior separation anxiety, where she would poop herself in the crate, whine, bark, etc. We did a lot of crate training and positive association (she loves cheese.. I give her at least half a slice broken up into many smaller pieces anytime she would go in there, feed her in her crate, any treats or rewards come from the crate, etc.). After a while, she seemed secure enough to not have her spend anytime I'm not home in the crate so I started phasing it out, which lasted a good 3 years probably.

Anyway, we recently moved to Hawaii a few months ago. She did great on the trip (certified her to fly in cabin, she slept the whole time and was very chill). I was prepared for some minor separation anxiety early in the transition, which proved to be true. She would shiver in the corner of the living room but eventually would chill out and sleep until I got back home. We have a good schedule going where I work about 6 hours and then get back, eat a snack and hang and then go for a nice 2 hour walk (~3-4 miles where she's off leash and allowed to explore at her leisure). We live in a nice, spacious house with a nice big yard. It isn't fenced in but she does well just hanging around our space. Her anxiety got better with each day until one day I left for about 2 hours only to come back to her outside waltzing around the neighborhood. I pulled into the driveway, which she noticed and came running back to our house. It seems she was able to pry open our jalousie windows (coastal windows), remove a couple of the glass panes, and break her way through the screen for the window. After a few iterations of trying to close, lock, and block the windows, she still manages to find a way out.

So I've been reintroducing the crate while bringing her to work with me a couple of times a week. She does great at work, just sleeps and hangs out.. she is the best dog when she's around me but I obviously cannot be around her all the time. But her anxiety in the crate has been awful. She's shoving it around, panting the whole time, barking, yelling, howling, which is all so uncharacteristic of her. It's heartbreaking and I hate seeing her so stressed. I do give her 600mg of GABA about 1-1.5 hours prior to leaving for the day, but nothing seems to quell her anxiety much. I don't know what to do. Does anyone have any suggestions? She is so anxious when she gets into the crate while I am preparing to leave, I feel like this is not the correct course of action. I'm happy to provide more information about our background and how the transition to Hawaii was. Please do feel free to ask. Thank you in advance.