Kudos to you for upgrading the Linux Kernel! Ubuntu 20.04 ships with Linux Kernel 5.4, and Canonical backported the Wireguard kernel module into Linux Kernel 5.4 for Ubuntu 20.04. For all other Linux distributions, Wireguard is officially in Linux Kernel 5.6.
The proof is in the pudding, on a fresh Ubuntu 20.04 installation run his command:
modprobe wireguard # executes successfully
then you can verify the wireguard module is loaded:
lsmod | grep wireguard
So you don't have to upgrade the kernel on Ubuntu 20.04, but it's fine if you do.
It's still free, it will show you an estimated price. But you are not charged this amount, because 1 f1-micro instance is free. Make sure you spin up the f1-micro instance in a zone where it qualifies in the free tier:
Hi Rajan, thank you so much for your wonderful guide and script to set up WireGuard + Pi-hole. Sorry to reach out to you but I have encountered an issue that I am unable to solve despite trying for weeks... I have successfully used your script to set up WireGuard + Pi-hole on a Ubuntu VM on my local network. Everything works perfectly when I am away from this local network (i.e. on my phone outside). However, when I get back home and start using WiFi, there is no internet (no DNS?) if I remain connected to WireGuard. Would you please let me know what's wrong with my setting? My father is old and he forgets to turn off WireGuard when he comes home, his phone would become disconnected from data because of this but he doesn't realize. Thank you again!!