There’s a clear theme to a number of your comments, and - genuinely without wishing to be facetious - are you familiar with epic fantasy series like Steven Erikson’s
Malazan Book of the Fallen or Robert Jordan’s
Wheel of Time? This type of series has a cast of dozens, if not hundreds of point-of-view characters - the idea of a single "main" character isn’t really how they work. As a result, the build-up of plot takes a lot longer as there is a much larger cast to introduce, and far more world-building to establish.
Bear in mind that the scale of these novels is exponentially larger than a 300-page standalone book; the full series will likely be closer to ten times that length. I wonder if perhaps you were expecting the book to be something that it isn’t. I don’t wish to dismiss your concerns - some of them are certainly spot-on - but while certain aspects are changeable, the overall scope and genre are not.