"Set up a ProxyVM as a VPN gateway using iptables and CLI scripts" does not work anymore

Hi,
since I moved to fedora-34 in 4.1-rc1 my vpn-qube does not work anymore. I set it up in fedora-30 according to https://github.com/Qubes-Community/Contents/blob/master/docs/configuration/vpn.md “Set up a ProxyVM as a VPN gateway using iptables and CLI scripts” and used it through fedora-30 - fedora-33. With fedora-34 it seems to be broken.
Funny thing is, it was working with debian-11…after I installed a bunch of software in that template it did not work anymore as well…

Any ideas or a better way to set up a vpn-qube with fedora-34 or debian-11 in 4.1-rc1.

Best regards