I agree that drafting a QB doesn't reset a GM's clock. There are plenty of GMs who have had the chance to pick multiple QBs. Letting a GM pick a new coach is more indicative of a clock being reset for a GM. An organization will rarely let a GM pick another HC if they weren't willing to keep the GM for another couple of years.
The second part.... not sure I fully agree with that.
In recent history, the NFL's model for success has been to build a solid team around a QB on a rookie contract. Philly has Hurts on a rookie deal, and they're stacked. The 49ers have Purdy on a rookie deal and they're stacked. Bengals have Burrow on a rookie deal, and they're stacked (Burrow is just injured). The Seahawks were most dominant with Wilson on his rookie deal. Chiefs were stacked with Mahomes on his rookie deal. The Chargers were able to add a ton of talent around Herbert, they just can't stay healthy. But the point is, they had the extra cash to attempt to make big moved. You get the point.
Sure, you can still have a solid team with a veteran QB on a large deal, but those QBs are usually the best in the league and you can afford to lack in other areas. Mahomes is a good example of that. They won one on his rookie deal, and the first year of his massive contract. But he's Patrick fuckin' Mahomes. Also, we're seeing how it's starting to impact them a year later with weak WRs and a stalemate with Chris Jones.
To improve our odds of winning a championship within 5 years, a rookie QB makes the most sense. If we hit on a QB, we've got the cap space and time to put together a stacked team around that QB and have a real shot at winning a Super Bowl with some luck.
That type of window for Fields is open for only 2 more years. We have quite a few positions that we need to strengthen to have a legit chance at competing, and I don't think we can accomplish that in 2 years.