Unable to sign into Apple TV on Samsung Phone

I am in the loop from ****. About 90% of the time when I try to access Apple TV+ on my Samsung it keeps asking me if I want a trial. I already have an account. It's random when it lets me access the app. I had to change my email address - which I was finally able to do so the account reflects that email address theoretically to use to sign in to the account and to access the Apple TV+ app. The phone keeps asking me to create an account and then tells me that account exists. I sign out and when I try to sign it it takes me to the screen to create an account. How do I get to the sign in screen so I can actually watch the programs. This happens 75% of the time and I finally give up and watch something else.