I make a version of this all the time. A few tips that I’ve found help to really make this work well:

Ratio of VWG to tofu. The ingredients list always say 1 block. But if you can’t get the exact one they recommend (the super firm) your ratio is going to be off. I use regular extra firm blocks, and I press the water out of them. My final measurements are 370g tofu:120g vital wheat gluten.

Internal temp. Seitan is just really dense bread. And when you cook bread, the recipes always include a temp. You want crispy French bread: 200f. You want a moist sandwich loaf: 180f. The same logic applies to seitan. I always try to get mine to finish at 190f. Too low, and the texture is weirdly gummy. And if you let it go above 200 it forms bubbles and becomes more like a sponge (you’ll see the outside edges get this way anyway.)

Compress it. Yes, wrapping it tight is key to not letting it expand, but it will naturally inflate. What I do is rest a cast iron on top of it after it comes out of the oven. Let it come down to room temp under pressure. Then rest it in the fridge overnight.

Those are the big ones. Good luck!