An NRI sale is not more complicated in principle. It is more complicated in sequence. Several things have to happen in order, each takes weeks, and starting them after you have found a buyer is how a three-month deal becomes a nine-month one.
Four things belong before the property is even listed:
Tell the buyer about the deduction at the first serious conversation, not at agreement stage. A purchase from a non-resident carries a higher TDS obligation than one from a resident, and the buyer also needs a TAN to deposit it.
The agent's job here is sequencing, not tax advice. PropVid's free NRI seller checklist is a Word document that lays the order out.