Struggling to Potty Train my Aussie at my Apartment

Betsy is fully housebroken, but because I keep getting sick, I thought it would be useful to teach her to go potty as soon as we go outside. That way, if a really bad day comes like I get the flu or I have to rush to work, then she can go potty right away, and we wouldn’t have to go on a long walk. Today was a bit of a fail day saved only by her best friend who happened to come out. Betsy is rewarded for going potty by getting to go on a long walk or play frisbee. And she always gets a treat for going potty outside.