Bad connection while having good internet

My internet is usually very good. I get about 700 mbps. For some reason, when I start up war thunder, the connection becomes terrible (5mpbs download and like 0.2 mbps upload). In war thunder this results in lots of packet loss and thus a bad connection with lots of teleporting around and things not loading. This affects my pc too (not being able to load any browser pages). When I close war thunder, all goes back to normal and I don’t have this issue with any other games. Anyone that might be able to help?