Nomadic in that case, it's much harder to answer the question since different apps have different ways of signing in.
Some apps might use your Google account to sign in (but you'd be prompted to allow it, they can't just access your Google account information). Some apps work like Google and have a shared account in "passwords and accounts", like I think Meta uses that feature. Some games use Google Play Games.
Maybe there are other ways of logging in quickly or automatically that I haven't thought of.
Regardless, without knowing what the apps are, we can only speculate.