Congrats, that’s a great route for your first QR business experience, especially in Qsuites.
Short answer: it’s very flexible. There’s no strict “three meals only” rule. On long haul Qatar business flights, dining is dine on demand. You’ll get the main meal services (like dinner and breakfast), but you can absolutely order additional items from the a la carte menu whenever you feel like it, as long as the galley has stock and it’s not during turbulence or crew rest constraints.
If you’re peckish between meals, you can ask for starters, mains, desserts, snacks, or even repeat items you liked. Some people do exactly what you saw on YouTube and try a bunch of dishes across the flight. Just be polite and realistic, and the crew is usually happy to accommodate.
AKL–DOH especially is a long one, so you’ll have plenty of opportunities to eat, sleep, eat again, and then still have breakfast before landing.
Enjoy it, and don’t be shy about ordering what you want.