Need some help with overcooked beef

Hi all!

So I just cooked a pretty delicious stir fry for my family meant for two days. I used beef round (800g, I think it’s like 1.5 pounds), sliced it thinly, soaked it in water and 1 tbsp of baking soda for 45 minutes, rinsed, drained, patted dry, seasoned and coated in starch. I fried it and it was perfect straight out of the pan. I then proceeded to prepare the rest of the ingredients and sauce, mixed it all (about 20 mins after I took the beef of the heat source) and served. It was borderline inedible and chewy. I think the sauce temperature might have been a bit too high when I mixed it which overcooked the beef. I expected this but didn’t realize it will be this bad. After a few minutes of trying to eat it I tossed it. Now I’m left with this batch for tomorrow - https://imgur.com/a/KkHFJf0 .

Do you have any ideas how to save it or should I just give up and waste it? There’s a fresh, high quality asparagus in it so cooking it for 2 hours now will most likely turn it into a pulp.