...and this is how things go if the President's approval rating is around 30%.
lol no
Note: that is an approval of 30%. He would get about 36% of the popular vote, which is as low as for any nominee for any Presidential nominee, incumbent or challenger, in a binary election.
This map
(1) may be unduly charitable for President Trump in electoral results with 20% approval, and
(2) sets a condition (30% approval) that I see unlikely to happen. I see 35% as a reasonable floor unless he does somethin unimaginable (and for now unmentionable).