Thanks for this summary on the Electoral College.
Yes, I'm familiar with the POTUS election system and how a candidate can get elected while losing the popular vote.

What I noted is merely that the Dems made inroads in states that Trump carried in 2016. I mentioned PA and MI in particular because Trump won them by only a few thousand votes in 2016 (I'm not a specialist, I just read Wiki). This might not necessarily happen again in 2020.

Also among the so-called "swing states", Florida was won by Trump with only 80000 votes (out of 9.4 millions); will it happen again in 2020? (I understand FL amendment 4 may have an impact too)