ECDSA is arguably better, but I agree that it is likely that neither will proof secure enough against quantum. However, that for what it is worth is all theory.
RSA isn’t used for encryption. They use 256-bit AES for that.
There is indeed no file-encryption using RSA here, from what I see. However, there is also no good excuse to encrypt metadata using it. It just isn’t a good idea. It makes no sense to use RSA here while better options are available.
Secure enough? maybe. Is it a well architectured solution? probably not.