Some are pretty good.
Some are pretty not.
They didn’t expect the successful of the first few that made the times best seller list, thats like massively more than they expected to sell, so they increased the planned number and the quality dropped massively as they expanded to the authors to suit.
If you read just the best books you’d still get the same favour but cut it to about 20 books or so, including the best ones in the Siege of Terra that are the actual ending.
Try this one for the best books, you won’t have all the plot lines but the main plot was decided decades before the series even started