Peacock and Data Cap

I've never done any streaming to watch TV over the internet (through my cable modem).

Now I see that I have Peacock and am wondering about data caps.  My account gets 1.2TB per month. I use under 200GB per month.

I was wondering how much data is used if watching, say,  a one-hour TV show.  I know it depends on the picture and resolution, and color, etc. , but was wondering if watching a few shows a night would go over data cap before month's end.  Here's my data usage:

https://postimg.cc/VdNVDDLD

I use a Comcast rented cable modem (not a gateway) and my own Netgear AC1750 wifi router. 

I assume that anything that goes through the cable modem counts towards the data usage cap.  If I download a program such as Firefox or Macrium Reflect, that counts.  If I watch a YouTube video, or download the video, or it's mp3, that counts.  If I watch a TV show on a Roku device connected TV, that counts.  Or, if I watch a TV show on my desktop via Peacock, that counts.

One more thing...if I use a Roku device connected to a TV, does watching a TV show count against my data cap?  It would seem so, since it still comes though my cable modem.  Also, I have three TVs that are connected to X1 devices (the other TVs in the house just have standard analong to digitla set top boxes).  I assume that any TV shows, podcasts, etc., that go through the X1 boxes, even though the data does not go through the cable modem, it counts against the data cap.

This stuff gets so complicated, that one might not know what the charges will be until the bill comes.  Reminds me of health care or cell phone costs.  Especially difficult for people that aren't technically inclined.

Thanks.

TIA