Cook the pasta in a large pot with salted boiling water until al-dente according to the package instructions. Reserve a few tablespoons of the pasta water before draining the pasta.
Heat a large skillet with a little oil over medium-high heat. Once hot, saute the sliced bok choy for 2-3 minutes, stirring frequently, then remove from the pan.
Reduce to medium heat and add the avocado oil and butter. Let the butter melt before adding the diced shallot, garlic, and red chili flakes. Stir frequently so the garlic doesn't burn but is fragrant, about 30 seconds.
Add the low-sodium soy sauce or tamari, oyster sauce, and gochujang paste. Stir until the sauce has combined. Then reduce to low heat, stirring occasionally.
Add the noodles to the skillet with the sauce over medium-low to medium heat. Using tongs, scoop the pasta up and glide it through the sauce until all the noodles are well-coated and glossy.
Stir in the bok choy and protein of choice. Top with sliced green onions and toasted sesame seeds before serving.