Doable... and Macau is cheaper. Skip Uber and board Macau ferry directly from Hong Kong International Airport (HKIA), as had already been suggested. Since this is an international transfer, you do not go through HK immigration; your passport will be checked when you land in Macau. If you're interested in collecting stamps, they no longer stamp passports in Macau and HK. When you arrive in Macau, take the free bus shuttle to Sofitel and from there you can walk to the history center of Macau. You can't leave Macau and not try Macanese food. My favorite restaurants are Henry's Galley or Restaurante Litoral.
The earliest ferry from Macau to HKIA leaves at around 7 a.m., so you won't be able to make it to your flight to PNH. However, ferries to HK/Sheung Wan run 24 hours a day, so you can return to HK with plenty of time to make it to the airport.
BTW you may be subject to HK airport tax (around $20) since this tax is not collected for transit passengers.