A good question.
A local answer.

Check baggage collection, domestic recheck and transfer requirements first, then work backwards from the second flight's check-in deadline.

On departure day, allow for peak-hour road traffic or public-transport transfers and the airline's check-in deadline.

Check airport pickup directions and any late-night service gap before choosing on price alone.

Compare the app's waiting and cancellation terms with requesting a car after you have collected your bags.

Confirm late check-in and the rental desk's morning hours so the overnight stop actually simplifies the trip.

Check the airline's recommended arrival time and the airport's overnight access before deciding when to leave your hotel.

Compare total time and effort, including stairs, luggage and the arrival hour. A taxi or booked ride can be good value if the public route involves several changes.

Confirm when your terminal, transport and hotel reception operate in the early morning. A prebooked ride can reduce uncertainty but still needs a traffic and pickup buffer.

Compare a taxi with a prebooked transfer only after confirming the actual arrival terminal. Include any waiting and late-night fees in the quote.

Check the current Translink fare for the city-only journey, and separate it from any Airtrain airport segment. An airport-service promotion may have different boundaries.

Compare the airport's minimum connection guidance with your scheduled time and ask the airline what happens if the inbound flight is late. Keep the booking reference handy.

Allow the airline's recommended international-airport arrival margin, plus extra time if documents need checking. The counter arrangement can change by flight.