2) I'm not sure why you'd be seeing problems then. If the black outs are always at a specific time in the video, please report those back here with the link and time and I can test on my side to see if I see the same. I can offer a few other ideas but it's hard to know what the issue might be since there are some many variables.
Try multiple devices
Try hard wiring if you're on a WiFi connection
Try different browsers
3) Yes, the speed feature available on many video sites can be an amazing tool. I'll be sure to request this for the Summit 2020 site. If there is a specific video you need to review and are having issues send me a direct message and I'll see if we can find another way for you to view it.