Usage has gone over 1TB after I bought a Samsung 75 inch TV

Around Christmas, I bought a Samsung 75 inch Smart TV and since then my data usage has almost doubled.  I am now passing my limit of 1.25TB each month.  All my other TVs have a Firestick which lets me exit all the streaming apps before I turn the TV off, the Samsung does not.  I can't figure out how to get out of, say Netflix.  It just keeps playing, so I just turn the TV off.  (The Samsung UI **). Does this mean, even though the TV is turned off, it is still streaming, or does it understand that the TV is now of and stop streaming?  Why has my usage gone so high?  We are not watching any more than we used to, just using a new TV.  Any suggestions would be helpful.