WireGuard Routing

[Unknown <jan lambertz one>]

Hi,

i've read
https://blogs.gnome.org/thaller/2019/03/15/wireguard-in-networkmanager/
and other sites several times and was happy to hear that routing should
be more automatic since v 1.20. 
Trying to use this feature aka "Routing All Your Traffic" , Table=auto
or wireguard.ip4-auto-default-route it seems not to work at all. I have
checked that the wireguard conenction is working in !not routing all
traffic mode. Maybe I am missing something obvious...
Here is the config, nothing crazy:
[connection]
id=WireGuard-VPN
uuid=a89a0b23-ce08-4364-b361-3c10c4b60327
type=wireguard
interface-name=wg0
metered=2
permissions=
timestamp=1610539928

[wireguard]
private-key=xxx

[wireguard-peer.xxx]
endpoint=ip:port
persistent-keepalive=120
allowed-ips=0.0.0.0/0;

[ipv4]
address1=10.10.0.100/8,10.10.0.1
dns-search=
method=manual

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
ip6-privacy=0
method=ignore

[proxy]

already tried to add wireguard.ip4-auto-default-route by hand, because
i couldn't find a knob for it in the gui but that had no effect. I'm on
debian bullseye with nmcli 1.28.0.
Maybe someone got it already working.

Regards,
Jan