I read that the tailgate light bars are a no go on the 2019's. The stamping isn't flat and wiring is in the way.
From my research;
This bar on a 2018 the spare hole was covered, some people installed them anyway
On my 2019 you are correct;
At first glance - the wiring for the tailgate is almost dead center and There’s some plastic trim pieces on both end being held in with plastic push clips/plugs.
My initial thoughts - fabricate/design some “stand off” brackets maybe even 3D print some
then you could remove the plastic push clips holding the trim in place and reuse them to secure the stand-off bracket. You would only need them to be 1/4-1/2” tall to clear the wiring harness.
This would also require buying a stick light bar not a soft strip.