There is a theory that development was restarted several times, most notably in 2018 to incorporate Keanu into the main story. It seems like they couldn't stick to a singular vision and shifted goals too many times.
https://kotaku.com/how-biowares-anthem-went-wrong-1833731964
It doesn't detract from the game or anything, but it just seems like an odd way to spend a limited development budget.
Even a lot of much older shows didn't need star power. Think about something like Star Trek TNG. The most famous person on that cast when it started was Will Wheaton. Obviously Patrick Stewart became huge but he was a total unknown prior.
I have no problem with them including Keanu in the game. I do have a problem with crunch and releasing a very buggy game.