Sign in with Google or Apple
Jinu offers sign-in buttons alongside the email link. On the website, in the iPhone app and in the Android app they are Continue with Google and Continue with Apple. Jinu does not offer sign-in with X.
All of them land in the same account system as the email link. Picking one is a preference, not a different kind of membership.
What Jinu asks the provider for
Basic profile information: your name, your email address and your profile photo. The sign-in request carries no permission to post, publish or share, because Jinu never asks for one. Nothing Jinu does will ever appear on your Google or Apple account.
Sign in with Apple and private relay
Apple can hide your real address behind a relay address. That works here, and it is the address your account is keyed to. Keep the relay switched on if you want it, but remember it is where Jinu's email will arrive.
Use the same one every time
Your account is identified by its email address. If you first signed in with Google using name@example.com and later use the email link with that same address, you land in the same account. Signing in with a provider that carries a different address (an Apple relay address, or a work address on Google) creates a separate account with its own listings and messages. If two accounts have appeared, use the address on the one you want to keep and leave the other alone rather than posting from both.
Checking which one you used
Open Settings and go to Login and security, under Your account. Sign-in methods names the provider your session came from, or says the account uses the email link.
If a provider button returns an error
Use the email link instead. It reaches the same account as long as the address matches, and it is the path with the fewest moving parts. If a button fails repeatedly, tell us at hello@jinu.app and say which button, on which device.