Various mods consider a protocol a "product or service".
You haven't asked the question you should have asked, and the question you did ask is off topic and not answerable even if it was on topic.
Closing it is the correct thing to do.
You are disputing the close reason which is:
Questions seeking product, service, or learning material recommendations are off-topic
Asking us to "find" a protocol is a "learning material recommendation"
My service provider has recently announced that it is updating its systems and will require a login using a social media account.
What your ISP uses for authentication has nothing to do with with accessing other services, for example email and social media applications/websites.
You just need to make sure your internet connection is live when your IoT device is trying to send an email.
My overarching issue is that I need to take an IOT device that sends out an SSL encrypted SMTP packet, and allow it to speak to a server that's expecting a social media based authentication like a Google or Facebook login. Which means that some kind of translation needs to be made.
You have an SMTP packet that needs to be sent to a mail server. You don't need a social media login to send an email. You need to ensure your IoT device is logged in the SMTP mail server when it sends that packet.
That is a completely different question from the one you asked which has nothing to do with sending email.
You were even told this in a comment on your 1st question:
Run your own email server that does support SMTP and TLS and forward the emails to that address
Connecting to a social media account
What protocol can I use to convert between the username and password that it tried to connect with and a modern social media login such as Google or Facebook?
As above, You don't need a social login to send an email. You are asking the wrong question.
Even if you did need one social media logins use a variety of login methods which may or may not include depending on how you have configured your logins (which you haven't specified). They may or may not be configured to use Two Phase Authentication
From the above is is unlikely that there is a single "protocol" as you call it that will handle the conversion you are after. And any such conversion is would be a complex process (which is not what you need as noted above).
And if there was such a process it would be a "service". And asking for Services is off topic.
You may have to roll your own. How to do this would also be off topic as then it would be a programming question.
You have also not specified what social media service you want to connect to.