I have hit the final crater you mentioned so often, I now manually visit the url /myorg/myrepo/compare/old-master...my-new-feature to start the PR instead of clicking "Create PR" or "Compare"
https://marketplace.visualstudio.com/items?itemName=GitHub.v...
pr !open "$(git remote -v | grep origin | grep push | cut -f 2 | cut -d " " -f 1 | sed -e "s|git@\(.*\):\(.*\).git|https://\1/\2|")/pull/new/$(git rev-parse --abbrev-ref HEAD)"