Vodafone requires no VLAN (despite some places claiming you need 911)
Assuming eth0 is connected to ONT, set its address to “No Address” and the MTU to 1508
Create PPPoE with ID 0 and eth0 as the parent. Add the username and password obtained from Vodafone live chat. MTU should be 1500. Yes, the username will start with “dsl” even though you don't have DSL.
IMPORTANT: Make sure to change the WAN interfaces in the firewall (port fwd, rules, NAT-masquerade)/routing to be pppoe0 instead of eth0.