The easiest way to understand the phrase, tip of the hat
is to think of a person tipping their hat to someone. It is done quickly without much thought.
The Trump tweet indicates that he (Trump) is advising people Mr.Biden will just close everything, raise taxes... etc. if things are not proceeding as he (Biden) sees proper.
The final words of President Trump's tweet, "not what the USA wants
" indicate that he (Trump) has no respect for Mr.Biden's plans.
Please be aware, Mr.Biden has not said all of the things which the President is alleging.