Line test is passing and router is in sync at 33.0Mbps. Your line profile isn't capping your speed so could you try switching your router off for 30 minutes then switch back on and retest
Could you connect your router to the test socket with a micro-filter and check to see if the speed improves, just to rule out any issues with the master socket faceplate
Line test is passing still but sync speed is virtually the same at 33.4Mbps. So you've just got the router connected to the test socket via a micro-filter, no other device connected to the micro-filter?