Depends on the time zone change. From Europe to with Africa sure a 12 hour figggt is great. If I travel business London to singapore i get far worse jet lag than if I fly via the Middle East and break my journey for a few hours.
Past like hour 12 it becomes really draining. I used to fly JFK to HKG and that was an ordeal; I can’t imagine the newer super long haul like London to Perth.