The main aim of proportional representation is to get proportional outcomes so that parties, or groups of representatives, are representing roughly equal representations of the voters. PR systems differ in terms of how proportional they are. They may use systems that are not completely proportional and that raise barriers for smaller parties, and so on. When you look at outcomes of PR systems, there is not one that is completely 100% proportional. In fact, proportional representation systems do a great deal better than FPTP systems. FPTP causes extreme distortions between the vote and the number of seats that parties get.
Several years ago I wrote an article that was titled Who Really Practices Majority Rule? I looked at FPTP countries and PR countries in terms of the amount of support that cabinets, governments, and executives have. Proportional representation systems tend to have governments that are supported by the majority of the voters, or close to a majority. In the examples that you mentioned, in FPTP countries, the winning party often wins with only between 30% and 40% of the vote, and that is not the majoritarian outcome.