You may or may not know this, but Uber Eats has a section that lets you filter out any allergies or dietary restrictions you might have. Instead of using the Special Instructions section of the app, you can now specify your needs through the Allergy section. The app will also let you filter through different restaurants based on your dietary preferences.
Restaurants will be able to identify allergies and take the necessary precautions when processing an order. If a restaurant can't accommodate your request, they can message you to let you choose other options that fit your restrictions.