"indie" or "true indie" is not the point here. It is success. For successful games you can find reviews on sites like https://www.metacritic.com/game/
There are literally hundreds of new games each day on Itch. How to select which games to review? Why select a game that does not even have comments or ratings on the platform it was released? Such a review site would essentially be no different then a famous youtuber showcasing random games. And the followers are not there for the reviews.
Imho, one either seeks information about a game one is interested in. Or one seeks recommendations from a trusted source. An unknown review site reviewing unknown games fulfills neither. So you have review sites reviewing all the popular games which include those you consider not true indie. And you have some recommendation sites with curators.
If you seek random reviews, try https://itch.io/feed?filter=ratings But those are also prefilterd by the frequency in which games get reviews, so another popularity hurdle.