Configure access point on Ubuntu 20.04 with the wwan0 interface

I have Ubuntu 20.04 running on Raspberry Pi4 and have a 5G HAT to get it connected to the internet. I have a wwan0 network interface with the IP. Now I'd like to make this network available as an access point to other devices. I tried to use a netplan, but it seems to work only with eth0 interface. Is there any way to make it work?