SOLVED: Directplay/Directstream constant buffering

[IceToast]

Interesting. Edge can direct play the same file but the issue is different. Instead of buffering every 2 seconds for 2 seconds (or similar) it's lagging and directly playing every frame it gets. So the playback is stuttering like you would play it in slowmo (hard to explain tbh).

JF Log:
https://hastebin.skyra.pw/azurupeduj.prolog

No packet loss in LAN and no real QoS enabled.