You won't see Heir to the Empire Thrawn in the Disney Star Wars television universe. Disney's version of Thrawn already spent 2 years getting consistently beaten by Ezra Bridger on Star Wars Rebels. He's still a good villain on that show, but the childish nature of that show means that he's not on par with his original book counterpart.
Seriously, if you want to see where Mandalorian's going, go watch The Clone Wars & Rebels. They cover ALL this Mandalorian stuff going on in the current show, and they are Disney Canon.