AppleTV Subscription (different ID) replaced iPhone Apple ID in AppStore!

Super frustrated... I signed into AppleTV on my iPhone using a different AppleID, and it changed my personal ID in the AppStore. I can't change it back to my personal AppleID, so can't buy the new app I want... Tried rebooting iPhone but still can't sign back in.

Specific details: I have multiple short-term rental homes with Roku TVs. Each home has a smarthome devices email account such as <###Street>. We recently moved retired and moved into one of these homes. My wife and I have iPhones (with Family sharing enabled). I signed up for AppleTV using the account that the Roku TVs at this house use <620W...>. This account is NOT part of Family Sharing (has been no need until possibly now). I Installed AppleTV app on one Roku, logged in, and it updated all the other Roku's in the house. Then, I installed AppleTV on my iPhone and logged into it with the home's email account <620W...>. Unfortunately, what that did was add AppleTV as a "subscription" and then replace my <chris...> AppStore ID with <620W...>. I've signed out of AppleTV and tried rebooting iPhone, etc and can't get the AppStore to log in with my personal account. It keeps saying "INCORRECT PASSWORD" yet, I can open Safari and Chrome and log into iCloud just fine with my personal AppleID and password.