You can't limit the bandwidth used to only that minute's worth of video, because YouTube is going to keep streaming more of the video into your buffer, which will use more bandwidth. Skipping to the middle will obviously skip over the first half of the data, but if you watch a minute and then just sit on the page, it will keep trying to load more.
On the web application, e.g on Chromium, you can click on the three dots and then on Disable video receiving. Then you can enable it again, and the menu looks like this:
The desktop application does not have such a feature as of this writing.
Jitsi Meet do not plan on providing an "Echo Test" service:
...we don't have plans to implement a pre-call device testing screen. While in a call though, you can open the device selection dialog and it will preview audio and video devices.
Posted at jitsi/jitsi-meet #1823
However, other hosts do provide echo tests, which allows you to at least test ...
This is a result of a bad downloader rather than YouTube throttling.
In DASH (which is what the new tech is called they're now using), a video is not just a single file that gets lobbed your way when you watch it, instead it gets sliced up into small parts a few seconds long each, so things like changing quality and adapting to a changing bandwidth (which ...
YouTube may be throttling its own videos. I can load all their front page material just fine. If I try to load a less viewed video and run it concurrently with a number of front page videos, the front page videos will stream perfectly and the unpopular barely viewed video will stutter and stop while continuing to buffer.