Some internet providers are traffic shaping!
The ISP is able to see the traffic and puts on limitations to the internet line.
Traffic shaping by your isp is a usual thing to do if too many connections are
detected to the same ip/url address hence some users from the same isp don't
Get any traffic shaping, if too many users using the same isp are connecting
to the same ip/url at the same time. Then the isp can! Traffic shape.
And in some cases will block the access.
Hence having a vpn does help but you need to keep changing the vpn
locations often, the isp locator does keep a record of the vpn servers location