Newly defined, by whom?
The role of POTUS is quite well defined here.
https://www.scholastic.com/teachers/articles/teaching-content/seven-roles-one-president/
Note the omission of
"Chief Twitter Whiner" and
"Chief Tantrum Thrower".
If those are the jobs he really wanted, he should have run in a different election.
When the Obama Administration took out Bin Laden, I don't recall Obama trying to claim personal credit, and he certainly didn't demand the families of 9/11 victims grovel in gratitude to him.
Mrs Trump, please get your angry, abusive child under control.