WiFi connects, but internet is only accesible with VPN active

Edit: I can access the internet just fine via the same wireless network using other devices

Other solutions I have tried to no avail Internet access only via VPN (Cisco AnyConnect), when VPN off - DNS look-up fails

No internet even though connected to Wifi network

Ubuntu 20.04 Wifi connected, but cannot access internet

Connected to wifi, but no internet [16.04]

connected to wifi but no internet - ubuntu 18.04

I am running 20.04 on a desktop with an external WiFi dongle. Following an update last week it appears something related to Network Manager broke. Prior to this update I could access the internet just fine with all the programs I normally use (apt, Firefox, Steam, Telegram and Signal desktop clients, etc) worked just fine. Post update it appeared that, while I could connect to the local WiFi, no program could actually access the internet. Later, by pure chance, I noticed that my Telegram client actually did connect to the internet at sporadic intervals, but no other program could do so. After some experimenting I realized that I could activate my ProtonVPN client, and with it active, all programs could now access the internet. Moreover, if I turn the VPN off I can staay in Discord calls for an additional ~10s before I lose the connection, but Firefox stops working immediately.

I have tried pinging my router, and that goes through just fine both with and without the VPN active, but only when I am connected to the VPN can I ping something external (e.g. www.google.com). This lead me to believe that the problem is not with any drivers.

After consulting various help guides I started suspecting the the problem lies with NetworkManager and I after trying a quick reinstall I decided to have a look at the config file from /etc/netplan/01-network-manager-all.yaml which appears to be rather empty(which may or may not be how it is supposed to be; content below).

nik@Bahamut:~$ cat /etc/netplan/01-network-manager-all.yaml 
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

After some more googling and the help of a friend I came up with a different config that took the control from NetworkManager and handed it to networkd instead (below)

nik@Bahamut:~$ cat /etc/netplan/01-netcfg.yaml
network: 
  version: 2 
  renderer: networkd 
  wifis: 
    wlx288088fc7609: 
      dhcp4: yes 
      dhcp6: yes
      access-points: 
       "WifiName": 
         password: *****

Changing the config file to the above, and following with

sudo netplan generate
reboot

Provides a partial fix. I can now access the internet with all programs except the VPN client that I rely on for work (FortiClient) and Proton, which fail to establish a connection. Before the change to the netplan config file Forticlient could only establish a connection if I first connect with Proton, but after the change neither works. Moreover, the change means I can no longer detect other networks. Unfortunately I have had no success adding this additional info to the original config file.

I have not voluntarily assigned a static IP to my machine, and for your consideration I temporarily disconnected my VPN to include some information that is often requested with these issues. IPV4 Method: Automatic(DHCP), DNS: Automatic On (have also tried with this off and DNS set to 8.8.8.8)

nik@Bahamut:~$ ifconfig
enp3s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 3c:7c:3f:ee:ca:e6  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device memory 0xfc600000-fc61ffff  

ipv6leakintrf0: flags=195<UP,BROADCAST,RUNNING,NOARP>  mtu 1500
        inet6 fe80::e2f8:fceb:167a:510b  prefixlen 64  scopeid 0x20<link>
        inet6 fdeb:446c:912d:8da::  prefixlen 64  scopeid 0x0<global>
        ether d2:ff:39:b1:7a:e5  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3512  bytes 506916 (506.9 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 29381  bytes 2269898 (2.2 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 29381  bytes 2269898 (2.2 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:cd:bc:f7  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlx288088fc7609: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.21  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 2001:1713:ea78:1550:773:6762:21e3:86b0  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::d353:1784:94c0:45a2  prefixlen 64  scopeid 0x20<link>
        inet6 2001:1713:ea78:1550:1158:6bf7:d17c:7159  prefixlen 128  scopeid 0x0<global>
        inet6 2001:1713:ea78:1550:ebe:ac4d:5487:c5da  prefixlen 64  scopeid 0x0<global>
        inet6 fdaa:bbcc:ddee:0:9850:84:44f2:c07c  prefixlen 64  scopeid 0x0<global>
        inet6 fdaa:bbcc:ddee:0:9557:a838:1dcd:b4c6  prefixlen 64  scopeid 0x0<global>
        ether 28:80:88:fc:76:09  txqueuelen 1000  (Ethernet)
        RX packets 3853331  bytes 4698645803 (4.6 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2672020  bytes 463156092 (463.1 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Thanks in advance