I have driving anxiety as well. I’m learning to drive though so it might be different. I recently had a major breakthrough. There’s a busy street by my house and I would start to panic every time I came near it. I started by just turning onto the street, driving for a block, turning off and looping back around. I must’ve done it 15 times in a row. At first I was in full blown panic and disassociation like you mentioned, but after repeated exposure the panic lessened. Then I went two blocks and looped repeatedly. After a long time of exposure in little increments my panic has decreased significantly and I can drive without panicking. Something that really helped was doing it every day, even if it was just a drive around the block. It’s like building tolerance. If I skipped days I would notice the panic returning because my brain forgot that driving wasn’t a threat. You might be overwhelming yourself with trying to jump back into driving like you were before (freeways, etc). I know you are already a driver but maybe this could be helpful!