As another European: proportional voting has nothing to do with it. Its more about ideologized voters who care more about ideology than merit when voting.
The natural balance of a system built on single member districts is two parties, which naturally has to oppose each other to the extreme in all topics. The final outcome is the US today.
See the radical shift when New Zeeland shifted to MMP, which although not perfect is better. [0] For party-list based systems some modification of the Webster/Sainte-Laguë method [1] is often used to have about perfect representation compared to the votes with the caveats you desire, e.g. lower thresholds and so on, while still allowing some choice in the actual person and not party representing you.
