I can definitely notice an improvement in performance when I use a VPN, however it would be cool to see where things are being delayed. Is traceroute or curl something that could help here?
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.
It could be the bandwidth limitation of your ISP itself.
Sites like Github are slow when accessed from few countries. It's just that their servers are located mainly in the US(afaik).
for example, stateful firewalls can only track a certain number of connections. If you don't have a public IP, or if they are trying to protect you, it may be necessary to wait for a connection resource to come available. Connections are generally expensive, different from data transfer, for these and other reasons, such as port starvation, syn flood defenses inappropriately targeting you, so many others.
tcpdump / wireshark would likely show lots of retransmits. Traceroute/mtr may give you an idea of where the loss starts. If you can find servers on similar hosting, you can get some idea of if it's targetted or not.