When setting up a stationary boom pole
I use a grip head like this
https://neewer.com/products/neewer-multi-functional-heavy-duty-2-5-inch-grip-head-swivel-head-holder-mounting-adapter-silver-10089719?_pos=2&_sid=63465f341&_ss=r

It has teeth and a spring to prevent slippage. But because of this, when I need to adjust the boom arm, loosening the knob does not immediately allow movement. I have to loosen it until the spring no longer can push the plates together, and then suddenly both tilt and pan becomes free and the boom pole goes flailing.

This is difficult to control. Is there a way to set this up so that the boom pole tilt can be adjusted independently of the pan, and loosening the knob(s) would gradually loosen the grip just like a tripod head?

Peter, you are missing one critical componenet -- a boom hook. This makes it really fast and easy to position the boom pole exactly where you want it. Plus, it is just held in place by gravity so it does not risk crushing or damaging the boom pole. I have two of them and every audio guy I've ever worked with has basically the same thing. This is standard in the industry.

https://www.bhphotovideo.com/c/product/885688-REG/Auray_BPH_BOOM_POLE.html/BI/2855/KBID/3801 (https://www.bhphotovideo.com/c/product/885688-REG/Auray_BPH_BOOM_POLE.html/BI/2855/KBID/3801/BI/2855/KBID/3801)

Forgot to mention I do have the hook as well. It actually makes the problem worse because it is not firmly attached to the pole (like you said, it's gravity), so when everything become loose, the hook rotates and moves around and the pole tries to slip out of the hook. It's like jenga game when one piece is loose, everything (not firmly attached) comes tumbling down.

The boom pole is held at a fixed angle. The height of the pole is controlled by raising and lowering c-stand column not changing the angle of boom with the clamp. This video demonstrates proper technique.

How To Setup A Boom Pole Without Someone Holding It - YouTube

Forgot to mention I do have the hook as well. It actually makes the problem worse because it is not firmly attached to the pole (like you said, it's gravity), so when everything become loose, the hook rotates and moves around and the pole tries to slip out of the hook. It's like jenga game when one piece is loose, everything (not firmly attached) comes tumbling down.

You have a boom hook? It doesn't sound like you are using the boom hook or grip head as they were designed to be used, or you wouldn't have this problem. Seriously, everyone in the business uses the hook/grip head and I've never seen what you describe.

The only way this can happen in when you introduce tilt angle and not a fixed 90 degree from the stand. Essentially, you’ve misunderstood the purpose of the adjustable bracket. Those teeth that interlock take the strain, not like the compressing fittings of mic stands, which all droop with heavy mics. These video stands allow much heavier weights to be held at angles other than vertical hence the turret style interlocking. That same arrangement as pan handles on big cameras. Booms need to be vertical.

When I was teaching in college, students always used to use them at angles (and miss the mouth) as it was easier on their arm muscles to put the end on your waist and have them go up at an angle. The muscle ache if having both arms up and the boom horizontal I suspect prompted the invention of the holder, for humane reasons!