Learn Dutch: De wijkraad zoekt draagvlak, dus daar wordt over gepraat. - The neighborhood council is looking for support, so that is being talked about.

The active verb is praten over (to talk about). To make a subjectless passive with a preposition, you usually use er + preposition (er wordt over gepraat). However, using daar instead of er acts as a demonstrative. It adds emphasis, pointing specifically back to draagvlak in the previous clause, meaning 'THAT is being talked about' rather than just 'it is being talked about'.

Since 'dat' means 'that', could I just say dus dat wordt over gepraat?

No, because you cannot combine a preposition with a regular pronoun like het or dat when referring to things in Dutch. You can never say over dat. Instead, it must turn into a pronominal adverb: daarover. In these prepositional passive sentences, this daar (or er) steps in to act as the grammatical subject, which is why it sits at the front of the clause.

Why is the word daarover split up by the verb wordt here?

In Dutch, pronominal adverbs like daarover (or erover) are frequently split. After the coordinating conjunction dus (so), the clause follows normal main clause word order. Daar takes the first position, pushing the finite verb wordt into the second position. The preposition over is placed later in the sentence, just before the past participle gepraat.