its always on standby (meaning the LED always glows)..however when we press the power button on remote it does say powering off or something like that..but LED still glows after it powers down.
LED glowing has nothing to do with being on Stand By. Unlike computer monitors that usually have an indicator LED that lights on when monitor is turned ON, this TV's LED is turned ON only when TV is not in use, whether it is Stand By mode or Powered Off. Again, with TCL TV's (most models) LED getting lit is an indication that TV and system is not in use. It can be on Stand By or Powered Off, it suggests that TV is connected to a live power supply. Once you switch off the power supply from your socket, the LED turns off or it turns off when TV is switched ON.
Anyway, about the Stand By that you are looking for:
Press the "Home" button LOGO on your remote (any of the two remotes) and when Android UI appears, go at the bottom of the rows, to reach the last row with "Settings" (True if you are running Android 7 - Nougat), OR go to the "Settings" located on Top Right Corner on Android Oreo TV UI. In "Settings", scroll down for the option called "Power". Open it. Here in this you will find the option called "Instant power on". Toggle it 'ON'. This is what you are looking for. Once this "Instant power on" option kept On, when you press the "Power" button on your remote or TV, you will put your TV to real STAND BY. Your LED power indicator light will come up as same as when you completely Power Off your TV. And, next time when you click the "Power" button, voila, your TV will come to life in just COUPLE of seconds.
I see that many people complain that this "Instant power on" is misbehaving with their TV; doesn't work at all OR sometimes work, sometimes don't OR it stops working when you keep your TV on Stand By for 30 mins or longer, etc. But, from my experience that occurs due to flaw in Android system. It occurs (again I am saying this from my experience) only because either you are running too many apps which keep running in the background OR (This is VERY IMPORTANT) you are running apps that are INCOMPATIBLE (side loaded apps, like Amazon Video or Prime Video app, apparently there are 2 types of Prime Video apps) or NOT MADE for TCL's Android TVs. Amazon Prime is the biggest culprit that keeps on eating your memory. Also, don't use shady apps like ES Explorer.
I am saying about all of the above errors in regards of Nougat. I have not got Oreo update yet, so can't suggest anything on issues with "Instant power on".
Apparently Android Oreo is said to be much better than Nougat, only time will tell.
But, I suppose you shouldn't be bothered about any of these issues because you only want to use the TV for TV viewing and as a monitor, am I right?
P.S.: To Power your TV Off, you need to press "Power" button 2 times (fast) or keep pressing the power button for 3-5 secs. This will bring the message on screen to Power Off, hit OK on your remote to Power Off your TV. After this, the LED will light will still be turned on, but when you hit the "Power" button again, whole 30-40 secs Android TV OS boot sequence will play on and your TV will only start after 30-40 secs. But, hitting the "Power" button just once, will put your TV in "Stand By" or "Sleep" mode (however you wanna call it).
Also, using a Voltage Stabilizer/Regulator is a good idea. Because, from my own experience and from the complaints that I have read about at many places, I can tell that even though fluctuations may not damage your TV's hardware unless sever spike or so, the fluctuations will cause TV to power off itself (again you would not know until you try to turn on the TV as there is no difference in LED indicator's behavior in between the Power Off and Stand By/Sleep mode) and then you have to go through the whole booting sequence.
Hope this helps.