Well if it’s for learning, you can rent vms from hosting providers. That’s a fairly inexpensive way to learn about BGP with a global “toy” CDN.
I have a small ipv6 subnet I purchased for just this purpose. It was interesting setting everything up in multiple locations and seeing traffic routing around as I turned machines on and off.
I also set up my machines as a reverse proxy of a sort, a small fake CDN, and experimented with caching at different locations and moving content around.
I would have gotten a bit more serious about it, but I’m still on the waiting list for an ipv4 subnet after 2 years. And pretty sure it would be too expensive now. Would have to check though.