[InsanelyIncredibly]

They have the same style though, and if you look at the Polsat graphics, clearly they're shaped similarly

They are not just shaped similarly - they are the same. One of the main complaints (as far as Polish TV fora are concerned) about Polsat's relatively new design is that the same design structure is being used across the entire portfolio - be it generalist Polsat, news-oriented Polsat News and Polsat News 2 or gender demographic-oriented Polsat Cafe and Polsat Play. Here, the case is slightly different because in branding Czwórka and Szóstka are theoretically separate as brands, so giving them the sun (it's not a globe) was not an option without ending up in an expensive rebrand. 

As for proof of how cookie-cutter Polsat's presentation is these days, here's a compilation of how new identity was introduced to all other Polsat channels back in 2021 - as you can note, the 'wave' motive is present everywhere, as is the case with Czwórka and Szóstka.