Although I don’t use egg white the first version is very similar to what I do (I’m normally combining with a marinade, so I’ll add more flavor at that stage - beer, Shaoxing wine, mirin, or something similar works, and spices / sauces to taste.
I’ve seen lots of mentions of the baking soda option but don’t care for it myself. Friends who have used it do indeed feel it does a better job of tenderizing, but I somehow always get the off tastes lingering even with the most careful of rinsing. Could all be in my head though.
This site -
https://www.masterclass.com/articles/velveting-beef
mentions the cornstarch velveting and is very similar to what I do, along with complimentary seasoning suggestions for the slurry, including the egg white from your video, and sauces similar to what I mentioned.
Now personally, I don’t do the two stage cooking from the video either. I’m sure if you’re only going to add the meat at the last minute, having it cooked/par cooked can be an advantage, but I’ll generally slurry ahead of time and when ready to cook it all goes in the same pan later.
Before the stir fry, get the beef back up to room temp (or if doing a short slurry and it’s not too hot, leave it on the counter the whole time). Since I lack a gas stove, I cook in a large, well seasoned cast iron skillet, and do my hearty veggies first (broccoli, ginger, celery, etc), then remove to the side, cook the meat hot and fast, and take out, putting on top of the other veggies. Last, any delicate veggies, or ones I want to preserve a bit of crispness (those bell peppers for example) and scrap as much goodness from the beef onto them. Then it all goes back into the skillet to mingle, heat and finish, often with a bit of the reserve marinate and slurry to make the whole dish more flavorful and add the glistening shine from the oil (sesame or neutral) and cornstarch.
You do want to be a bit careful that you don’t damage your seasoning, but if you don’t let the final stage go on too long (just enough to make sure no raw elements from the slurry remain, and to heat the cornstarch enough to thicken) it should be fine.
Again, lots of additional things you can do to customize the dish. The aforementioned toasting of slivered / sliced almonds to top, almond butter or peanut butter in the slurry if well blended, lots of extra capsicums, finishing oils, such as a sesame chili oil, or even adding a fried egg (chicken on chicken as it were).