First and foremost, in any discussion concerning Lincoln and his political leanings, it's necessary to examine the Republican platform in the 1860's vs the Democrats of the day and how, over the intervening century and a half, the 2 parties effectively switched platforms. If Lincoln were alive today, there's not a chance in hell he would identify as a Republican or support their political ideology and would be the first to call out Trump.
https://www.livescience.com/34241-democratic-republican-parties-switch-platforms.html
The Southern Strategy is a myth. For all his faults, Nixon's record with race relations and minority rights was pretty damned good. Detail me when or why the "switch" happened and I'll explain where the timeline and demographics simply don't support that narrative.
https://twitter.com/realDonaldTrump/status/1340701616010375171
https://www.livescience.com/34241-democratic-republican-parties-switch-platforms.html
https://www.washingtonpost.com/outlook/2019/07/26/what-we-get-wrong-about-southern-strategy/