You are asking question and answering yourself.
If you lost Bitcoin files and you still have the passphrase all you need to do is create an account, log in, go to settings, and click the addresses where an option to import BTC addresses will appear. After entering your private keys, you should be able to access your wallet once again.
Not passohrase but
seedphrase, but if passohrase is included, you will also need to include it when importing the seedphrase, so the wallet will generate the right keys and addresses.
There is nothing like login about wallet, it is not an exchange account or custodial service, you have the full control.