1: My website title.
2: My text title
3: Another text title, but while every post should have a site title, this post has a title.
proof that this is not about me.
What appears in Google search results is completely automated by Google, you don’t have much control over it other than providing some hints via the <title> and <h1> elements etc.
Is it possible that Google has picked up your “related posts” section and taken the first <h2> from that to show as a sub title in the results?
I don’t think so because the suggested post below is same for each post. Articles titled GTX 1060 and GTX 560 Ti. There is nothing to do with 1050.