Log Out on an iPhone Retains Last User Login and Automatically signs back in

Using an iPhone with Appsheet installed to run application(s) that should allow different users to use the same device but under their own login. When I first start Appsheet on the iPhone it asks the service (Google in my case) and then proceeds to login. Now at the end of my session I go to the App menu and choose ‘Log out’. When I go back to Appsheet it requires the login (as expected), I choose Google from the options, rather than giving me a login screen to login under a different Google email it somehow retained my prior login info and just logs me back in under that account. This result is undesired as I would like to have different users with their own email to login if I tell Appsheet to explicitly log out. Furthermore, this could present other issues, which I don’t think I need to go into detail about. But in the end why is Appsheet just automatically choosing my prior log in without the possibility of changing accounts. How do I correct this since this is a shared device. The phone does not have a link to the Google account I used other than through what I provided in Appsheet.