To add to PhilC's sage advice, you want to start with your figure not only at zero pose, but also zero morphs. This is part of the magic of dynamics - the bit I'm incredibly impressed with - is that by frame 30, all your morphs will have come back and the cloth will have followed, with a perfect fit. The clothing item needs to fit completely with no breakthrough/pokethrough anywhere at zero pose/zero morph: this is crucial. Check 'round the back too, just to be sure.

I always let my sims run at least 30 frames. Think 30 frames/second (like in the movies) - can you go from the zero pose to the pose your figure is going to end up in in one second?

The following approach works for me as a starting point for doing dynamics:

--Have your figure in a standing sort of pose, for a dress, for example. That way, the dress only collides with the figure without a lot of bending and stretching.

--Make sure that the cloth does not intersect with the figure anywhere.

--Load your figure (say, V4) and pose her in either the default zeroed pose using the joint editor, or using whatever the cloth maker provided for zero-pose. Zero all morphs as well if you have an morphs dialed in.

--Check that your figure isn't translated anywhere from 0.

Let's say we use the default 30 frames. Go to frame 30 and make it a key frame. Pose your figure.

• In frame 1, load the cloth to be clothified on your zeroed figure. There should be no poke-through anywhere.
• In Cloth room, set up a new sim. Click on New Simulation...
• For Simulation Name I tend to call it by what I'm clothifying: short version. The only other change I make in this dialogue is to tick the Cloth self-collision tickbox... and Ok.
• Cloth Objects, click on Clothify... oftentimes your item will already be selected. Otherwise, you'll need to find it. Remember, it's a prop, not a figure. Click Clothify.
• Colide Against: click on the Add/Remove button and select your (V4) figure. Set collision Offset to 0.25 and Collision Depth to 0.2. These settings have worked an absolute treat for me for the past few days for all sorts of dynamic, hybrid and even conforming cloth that I've clothified, so I share them with you (thank you AGAIN!, KobaltKween!). Please keep in mind your mileage may vary.
  Tick Ignore head, hand and feet collisions (if in the end pose the cloth doesn't have contact with any of these), and click okay.
• Click Calculate Simulation.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks