You’re not using the app are you?
Avoid the app at all costs. Use the web site. I can log in there with nothing but a username and password.
The stuff you’re describing sounds like it’s setting up a passkey and tying it to Windows Hello via a face scan.
None of that is needed, but even if you use passkeys (which you should), you don’t have to do a local face scan to unlock it; you can use a password or (better) a token such as a YubiKey.
In all these cases though, LinkedIn isn’t doing a face scan; that’s just your designated way to unlock your locally stored passkeys.
Yeah; that’s passkeys in action. It’s your Android phone setting up the passkeys vault that’s doing the face capturing, not LinkedIn. LinkedIn is showing you the QR code as a means of using passkeys for verification.