I have multiple accounts for a given website. AccountA, AccountB AccountC etc.
At the moment to login to the same website using different accounts on the same browser (At different times, not concurrently) without being tracked by cookies/IP address what I do is I open an incognito session, go to website and login with AccountA. Do my stuff on the website and then close the browser.
Then to login with AccountB I turn ON & OFF flightmode to get a new IP, and start a new incognito session and login with AccountB. And so on for each account.
What I want to do is create an app that I can launch, select the account I want to login with (Maybe have list of accounts stored in a local flat file )and then have the app look after making sure there is no other session running, turning ON/OFF flight mode, populating the login user/pwd fields, login, allow user do their stuff in the browser and then exit and allow user to pick the next account to use. App can be iOS or Android but ideally Android. The browser that is used can be any available browser that runs on Android or iOS.