as far as operations go, I would recommend joining via "Join Any Operation" rather than a particular operation, if you want to jump straight into the action.
October 2017 - last edited October 2017
It'll depend on the operation, some are more active than others and sadly They Shall Not Pass operations are a lot more empty generally than the DLC 2 or base game operations. That said I've had more success joining 64 player Devil's Anvil operations than I have Soissons though you may want to keep trying since it'll often match you into an empty game especially when searching with friends.
That said, the DLC operations including the TSNP ones are generally active during premium trials / friend events.
I have the same issue. I search for a game and just get placed in a completely empty lobby. This happens like half of the time and since battlefield insists on showing the extremely long intro for every operation it sometimes takes up to 15-20 minutes to find a game. It is incredibly annoying and really needs to be fixed