Had the same problem, I found the problem with my ISP , you can do speed test to different servers in speedtest.net . I observes a huge decrease in speed to many servers. This is mostly cause my ISP had bad peering to most servers. Only nearby servers gave full 200Mbps speed. Even some within same country agave <50. The single connection speeds would mist likely be less cause of your ISP’s bad peering. This doesn’t mean you won’t ever get the full speed . when multiple connections are made from different places they would be using the full 1gig speed.