I would love to see a study done to answer if modern news papers has become more partisan compared to the past. While perfect objectivity is not likely, I can imagine such study showing that news organizations where more political independent in the past with fewer political donations, fewer ties to political parties, and with a more diverse reader base over the political spectrum. The later was for example studied for the 2016 and a very tiny portion of US news media showed a diverse reader base, with most having the wast majority of readers in one political camp. If we had a similar study for say 1950 we could compare.
From a German perspective I don't think German media got more partisan. They rather became more clickbaity.
A notable difference is that it's simpler these days to read and compare different media, as well as looking at excerpts.
To the last point: Historically you got the complete paper and a good™ paper shares different oppinion pieces (even if main oppinion of a paper had one view, publishing opeds with opposing views is/was normal) however nowadays one doesn't look at the full package, but only clicks on single articles (probably spread in like minded FB/"social media" groups.