Have you read here yet?
I’ve started experimenting with RTKonnect to inject NTRIP corrections to various brands. Haven’t looked at Deere yet.
You’ll want copies of BNC and SNIP demo to tinker with. I’ve been down this path trying to get AgLeader Paradyme working and figured out my NTRIP source wasn’t including some of the legacy messages. SNIP demo can show you what is already in the message tream and can recreate several legacy messages that might be necessary.