Searching on completion rate brought up varying levels. Movies are higher, which I guess makes sense, but it doesn't feel fair to judge shows and movies exactly the same.

Best example I could find was that Netflix cancels shows if they have under 50% completion on the first season. On the flip side, Netflix has cancelled some good shows that way, so I don't know that this is a smart metric to use, but it does indicate that Rings of Power performed poorly either way.

A lot of stuff gets cancelled even with way higher completion rates. Inside Job had a 90% completion rate for the first half of the season, and the dip to 58% with the release of the second half was bad enough that it was blamed for the show getting axed.

Streaming doesn't seem to be very good at standardizing numbers, though. Batch episode releases vs weekly releases vs split season releases seem like the kind of thing that would push numbers this way or that, but there isn't a universal metric. This appears to be the best available data, but it could be better, yeah.