BPG is like international shipping... it has to be there for the world to function, but most people don't need to interact with it.

One way to play with it is something like this: https://www.eve-ng.net/

The other is to make a couple of virtual machines with a couple of network interfaces, make some sort of network betweeen them and then use some bgp routing deamon, eg:

https://bird.network.cz/

https://www.nongnu.org/quagga/

etc.