To expand upon the Polish Go Championship example, the decline in its coverage over the years really demonstrates the problem.
2016 had a great forum post organizing all of the information
2017 does not seem to be mentioned in the forum at all
I don’t know if the games were actually relayed or not. Maybe @Revar_Isave or @silk would know?
2018 has a (partial?) catalog of the relay split over two posts
Auxiliary information is missing and the organization isn’t that great, but at least one can find some of the games.
2019 seems to be missing from the forum as well
However, I know that the tournament was in fact relayed (see picture in the original post), and there was even twitch stream for commentary. In theory, all of those game records are sitting on the OGS server somewhere, and the twitch streamer has probably archived the commentary stream as well.
Unfortunately, given the ephemeral nature of the notifications, it’s very difficult to find where any of that is located, or even know that it exists at all.
Note: this is as much an issue with those relaying tournaments as the current notification system. It’s surprising to me that people will go to so much effort to relay an entire tournament, but then let all of their work disappear into the mist by not archiving it anywhere. Wouldn’t they want to have people know about it both before and after the event happens?