I wouldn't enjoy playing in your games
at all.
Did you post here asking for help because your players are getting frustrated over your DM'ing style and you want to change it? Or are you just bragging that you
win D&D all the time?
I don't understand the logic behind a DM that TPK's so often. Killing PC's is the easiest thing in the world to do as a DM. Whenever I hear this, I don't think, "Wow, this DM must be really good & one of those RBDM's!" Instead, I think, "Man, this DM sucks at running encounters."
Challenging PC's is an art. You need to know how & when to throw that easy/moderate/even/hard/killer encounter at your players. If players are getting TPK'ed left and right...I believe it has more to do with the fact you aren't good at making proper encounters more than it has to do with you being good at making hard encounters. Any DM can throw a killer encounter at PC's, that's so easy. Any DM can throw an easy encounter at PC's, that's so easy too. But not every DM can throw an encounter at PC's to make them crap their pants...yet still have a chance to survive without it being a TPK. And if you're the type of DM that lets the dice fall where they may & rolls out in the open, you better be extremely good at balancing encounters throughout the adventure.
Why are you adversarial towards your players? I personally can't stand DM's like this and I would never play with one. Playing against a DM is pointless because he knows all & sees all, and can do all. A DM is not limited...players are. If I wanted to play
against the DM, I'd invite him over for a game of Chess or Stratego. Or if I just had to play D&D rules, I'd roll up a character and just tell him, "Ok, pick something from the Monster Manual and lets fight each other". Otherwise, it's pointless to call your game a "campaign" if no one makes it far in your world. All you turn it into is a board game. If that's what you want, cool...I'm not criticizing that game style, it's just not my style.
When your players say, "Dang, what CR was that?", do you tell them? Do they complain about it being too high? Are you throwing too high level CR's at them? Are you throwing too many high level CR's at them? If your fights truely are balanced like you say, there's nothing wrong with wanting to smack on the PC's & enjoying when your cool NPC does it. We all do that

I just don't purposely shoot for a TPK. If it happens it happens, but I will try to not let it happen because a TPK is as annoying as when someone accidently knocks over your chess board in the middle of the game.
Don't get me wrong, I wouldn't want to play with pushover DM's either. I prefer a DM that can whoop my butt to the point where I think we're about to die, but gives me a chance to save the day if I figure out a way. If I play smart, I survive, & if I play dumb, I die. I don't have fun playing with a DM that kills me no matter how smart I'm playing. If you are TPK'ing all the time, you're doing nothing different than throwing a CR 20 NPC at 1st lvl PC's (give or take a few levels)...no matter how smart I play against the CR 20 NPC, if the DM is out to kill me than I'm not going to survive.
Basically, I believe most players prefer the NPC's to kill them rather than worrying about Gundark the DM killing them.