You absolutely DO NOT require a visa regardless of how many tickets you are traveling on. You will also struggle for time to clear immigration, collect luggage, clear customs, head back upstairs, checkin again, clear immigration, clear security and board your next flight if you choose to go landside.

In contrast, you can head directly for the international transfers desk (there is NEVER a line there and it is very well signposted) where your boarding pass can be issued in 30 seconds flat and then to the dedicated security checkpoint just beyond. If your bags are checked through, you can be at your next flight departure gate within 2-3 minutes of disembarking your inbound. If they are not checked through, give your tag numbers to the staff and they will make the necessary arrangements to retag the bags.