So if I understood correctly, you’re asking whether a modern airliner can be flown by remote control, rather than it flying on its own.
The answer is yes, certainly -and the availability of fly-by-wire is irrelevant.
Remote control is not a new technology and it’s been and is used to control aircraft remotely. The earliest use of remote control in real-sized aircraft -as far as I can remember- was during WW2. The USAAC tested the feasibility of using remote controlled, bomb laden, decommissioned heavy bombers to attack fortified structures in Operation Aphrodite. They used B-17s and PB4Y bombers. There were also a number of remote guided flying bombs, especially in the German inventory. Though they’re not an actual aircraft per se, the same principles apply when it comes to remotely controlling them.
NASA used remote controlled airliners for crash tests. First in 1984 using a Boeing 720, second in 2012 using a Boeing 727.
The Air Force and the Navy has been using remote controlled aircraft like F-16s and F-4s (on the modern end of the inventory) as drones for decades.
The technical side of it is a definite yes. Other aspects are another story.