Looks delicious, but also like a lot of effort for preparing seitan to me. I make seitan 1-2 times a week and it doesn't take me more than 20 minutes in total.
I buy powdered gluten in bulk from a bakery wholesaler (5 kg per pack). It's relatively cheap and saves me all the effort and mess of washing the flour. Also, if you start from flour, you have a lot of starch water as a byproduct which I couldn't utilize properly.
I often use similar spices like in the video (soy sauce, smokey powdered paprika, chili flakes, pepper, salt, some sugar, lemon juice, ...) but instead of adding it to a broth, I just add it to the dough right away. Then, I add some water (not too much!) and knead it until it gets the texture of chewed chewing gum, maybe slightly firmer.
Instead of cooking or steaming, I just microwave the dough. If you use a shorter time (4-5 minutes) with a high wattage, you'll get a lot of pores that make your seitan look a bit like bread (but with a different consistency). If you go for a lower wattage and longer time (8-10 minutes) that effect will be reduced. If you want to have an even denser result, you can put your dough inbetween two plates while microwaving so you have some pressure from the top that further reduces the expansion.
After the microwave, let it cool down until you can touch it and you'll have a very similar result as shown in the video that you can tear apart with a fork, slice or dice it as required for your recipe. If you want to have it crispy or give it an even color, you can fry the result with some oil in a pan.