[Retric]

Yea, if it’s faster via VPN that’s a strong hint. If you want proof you need to examine the internet between you and the site. If a VPN connection that uses a specific router to to the site is fast, your connection through that same router is slow, and you can connect to some other site through that same router and get a fast connection, then that’s a smoking gun that your connection is deliberately slowed.

That said, it’s not easy to prove it’s your country/ISP doing the slow down vs that website slowing down connections to your country.