Learn Polish: Warto zdobywać wiedzę poprzez samokształcenie. - It is worth gaining knowledge through self-education.

While both mean 'through' and take the Accusative case, poprzez is used specifically for abstract, methodical, or structural means of achieving something. Since samokształcenie (self-education) is an abstract method rather than a physical space you can walk through, poprzez is the more natural and advanced choice.

Does poprzez change the case of samokształcenie?

Yes, poprzez requires the Accusative case. However, samokształcenie is a neuter noun (like most verbal nouns ending in -nie). For neuter nouns, the Accusative form is identical to the Nominative dictionary form, so the word looks completely unchanged here.

Could we use the perfective verb zdobyć instead of the imperfective zdobywać?

You could, but it would change the nuance. Using the imperfective zdobywać emphasizes that gaining knowledge is an ongoing, continuous process. If you used zdobyć, it would sound like a one-time task to complete a specific goal, which doesn't fit the lifelong nature of self-education.

There is no subject like 'you' or 'we' in this sentence. How does warto work here?