BTW: anyone who wants to really experience how complex internet routing is, go and join DN42 (https://dn42.dev). This is a fake internet built on a network of VPN tunnels and using the same routing systems. As long as you're just acting as a leaf node, it's pretty straightforward. If you want to attach to the network at multiple points and not just VPN them all to the same place, now you have to design a network just like an ISP would, with IGP and so on.