Learn Italian: Sembra ricco, ma in realtà non ha niente. - He seems rich, but actually he has nothing.

Attualmente is a classic false friend! It does not mean "actually"; it means "currently" or "at the moment". When you want to say "actually" to point out the real truth of a situation, you should use in realtà (literally, "in reality").

This lesson is about markers like infatti. Could I use infatti here instead of in realtà?

No, and this is a common trap! While infatti often translates to "actually" or "as a matter of fact" in English, Italian uses it exclusively to confirm or agree with what was just said. Because this sentence contradicts the first part, you must use a contrasting marker like in realtà.

Why does it say non ha niente instead of just ha niente?

Italian relies on a double negative structure. Whenever a negative word like niente (nothing) comes after the verb, you are required to place non before the verb. While it translates literally as "he does not have nothing", it is the grammatically correct way to say it in Italian!

Could I use però instead of ma to mean "but" here?