There are no "official" or "trusted" instances. The instances listed on Invidious' site meet (or should meet) a certain set of criteria. Several of those items could be considered bare minimum for hosting any website over 10 years ago (eg: be served via https, must have a domain) or are about other availability metrics. I'm not saying you shouldn't trust any of those instances, but just want to clarify that it doesn't necessarily mean that the instances are endorsed or trusted by the Invidious team. Instead, it is just a directory of instances that meet some minimum criteria.
I didn't check all of the instances currently on the list, but instances that were previously on the list did not proxy all traffic from YouTube. Since this is not an requirement to be included on Invidious' list of instances, I assume that there are likely one or more instance that is not proxying the YouTube traffic.
If the traffic is not proxies, then your browser will interact directly with YouTube's servers for some content (typically the actual video content). While this prevents you from interacting with YouTube's frontend (and all the tracking that comes with that), it does not prevent YouTube from identifying which videos were served to your IP address, which parts of the video were requested, or other identifying information.