For instance I tried to update my prime video, and Amazon tells me I have to go to the website to manage my subscriptions. So I try to go to amazon.com and Firefox, and it opens the app instead of the website. So how do I get to the website so I can manage my subscriptions?
Huh? You’re opening your browser, and going to amazon.com and it redirects you to the app?
I’m assuming you’re on mobile. Try using your browsers incognito/private browsing feature- you’ll probably have to login again but it should prevent app redirects like that.