I loved the first prequel (going to check out 1923 this week), but I have a feeling the prequels are actually contributing to the decline in quality of Yellowstone.

I don't know any of this for certain, but in my opinion, it almost seems like his plan for Yellowstone is to have all of the prequels lead to its culmination. At least with 1883, it 100% showed how the ranch came to be and tied into the present-day series by explaining that the family would have to return the land in seven generations. So the prequels are definitely building up to the end game of Yellowstone and aren't simply there JUST as an extra little spinoff for fun. They're actually serving a purpose in the grand scheme of things.

But the downside of this is that I get the vibe that Yellowstone is just meandering and killing time until the prequels can run their course. They are going to milk the main series for all it's worth so they definitely won't just take a hiatus or anything, but at the same time, they seem like they are stalling the story until the appropriate time to move forward.

Everything they do in Yellowstone now is just meant to maintain the status quo. No main characters are ever really in danger, they hardly evolve, the overall plot moves at a snail's pace, etc. It just never progresses because they don't want to do anything drastic just yet.