Supplier Portal Outside User-Facing Link

Summary:

We are wanting to understand if there is any method for us to use without suppliers actually having to log into the supplier portal.
Currently, in production, we can only use SSO, and if we implement supplier portal, we cannot have our suppliers log in using SSO because they don't have credentials with our domain (i.e. xyz.abc@defg.net). What other solutions are out there? Is there an outside-facing supplier portal link for example that doesn't require login?

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