Palo Alto Global Protect is broken under linux. A third party tool works absolutely flawlessly, I gave the guy $25, frankly PA should hire him.
https://github.com/yuezk/GlobalProtect-openconnect
For debian bullseye add the repo and change the distro from mantic to bionic. You may need to manually add the keys:
apt-key adv –keyserver keyserver.ubuntu.com –recv 53FC26B43838D761