MTU Values for PC and Router in a nested VPN tunnel?

It’s like putting a needle through a hole inside another needle.
2 Wireguard tunnels, pc’s tunnel goes inside the router’s, so I would think it should have a smaller MTU set?

However, I don’t understand how I can ping with up to 1472 MTU without errors. They say 1420 is max for wireguard?

• Only IPV4
• PPOE

Setup simply looks like this