Both the primary WG and my secondary WG got totally screwed up and wont even boot in an orderly fashion.
Luckily I took a backup before venturing into testin.
As a workaround, I installed pfSense on proxmox, hooked up my VLANs and now this technically works. Technically, not optimally - because now I'm firewalling in the host-environment where my crownjewels are, instead of firewalling before even touching this hardware. But for now, I'm in business again.