Too early to make predictions, but we must not forget that Trump's approval rating was close to 50% when he got those 77 million votes.
Now his approval rating is close to 40% and trending down.
In my estimation he has two choices in the next 12 months:
He can change his ways to project a softer and more Reaganesque image.
Or:
He can declare that the midterm elections are being rigged against Republicans by the Democrats (and their terrorist sympathizers) and put all elections on hold while an investigation ensues.
An investigation that might go on for a long time.
And how many protesters would be in the street if that happens?
These are indeed fascinating times in American history.
		
		
	 
You clearly have little understanding of politics or the current political landscape, and watch far too much TV... 
Almost universally all POTUS start their tour with high approval ratings, and equally almost universally, they ALL see their approval ratings drop over time.. Thats the nature of inspiring lots of people to vote for you, and then facing the cold hard fact that its impossible to please all people all of the time on any single issue.. 
For example, probably the second most popular D president in modern times, Obama, hit a 40% approval mark in Oct 2014.. Far and away the most popular D president in modern times, Clinton hit a 37% approval rating in June 1993... 
So.. what exactly is it that Trump is unpopular about? and where does he remain popular?  And how much impact do any of those things have on future elections? Well... since he isnt running for office again, his personal popularity has little to no impact on him at all... And, oh, by the way, the things that typically matter in presidential elections like the economy is still polling at about 55% according to Real Clear Polling... 
Where his popularity had largely declined, which impacts the aggregate 40% value being reported is on healthcare issues.. 
Well.. no shit... healthcare is the #1 reason the D party has pushed for the govt shutdown.. its the only hill they have left to stand on that anyone gives a damn about nationally.. 
Where you should be looking is at CONGRESSIONAL approval ratings.. since the house and the senate will both be seeing elections next year.. 
Currently Republican members of congress have a 69% approval rating per the PEW Research Center (generally seen as one of the least biased research /think tanks).. While Democrat members of congress have a 40% approval rating (per PEW).. that is a HUGE gap... even NPR (clearly left biased) rates Democrat congressional approval at 48%.. which is still a HUGE gap between R and D approval ratings.. 
As a result, Trump has no motivation to do anything that you describe.. his antics MAY harm his own approval.. but who gives a shit? Its clearly not harming the R's in the house or the senate.. its not harming any of the would be 2028 contenders to replace him.. take a look at Rubio, DeSantis, and Vance's individual approval ratings.. and Trump isnt running for re-election..