Current Trump popularity map by state (you have to scroll down slightly).
[morningconsult.com]
Strongest support for Trump is in Alabama (always has been insofar as I have been tracking state approval polls).
Florida and Montana are now 50/50. (Montana is surprising to me, but his support has been weak there for a while.)
Wisconsin, Michigan, Pennsylvania, Ohio, Iowa, North Carolina, Arizona now have Trump's approval underwater (he won those states). It's hard to believe Trump supporters are still lying to pollsters in shame at this point, but it is possible.
Notably, Indiana and Nebraska have Trump only up 2%.
Texas notably only has him up 4%. (That's TEXAS. I doubt it will flip in 2020, but it isn't outside the realm of possibility. 2024 and 2028 are not far off, and if Texas politics flips, the board fundamentally changes.)
Trump's lowest approval is in Vermont, Massachusetts, Maryland, Washington, and California.