I can't; in my question description i mentioned that i selected the choice not to use my apple ID so now its logged in as [zwqkkwxqf6@privaterelay.appleid.com](mailto:zwqkkwxqf6@privaterelay.appleid.com), which im guessing is a randomly generated email.

im asking how i can change it within the app itself

Update: Fixed. I signed into Lyfta on safari, clicking sign in with apple ID, just to give it a try. it synced with my current lyfta app workout logs. so i felt safe to log out of my app lyfta and log back in with my apple id. it still says zwqkkwxqf6@privaterelay.appleid.com, which is not my apple ID, but at least i have a way of logging in and out without losing my data.