This is not true. "Millions of emails" was in reference to this part of the warrant:
"Communications between Twitter and any person regarding the account including contacts with support services and records of actions taken"
"Communications between Twitter and any person regarding the account including contacts with support services and records of actions taken"
That item means they have to hand over things like support tickets or emails sent to the @realDonaldTrump account or Trump's social media team.