Congratulations on that comment.. I bet that made you feel good!
I said in the original post there is not enough on the cable to put a plug on. The sheath is stripped all the way back beyond the box. So maybe you should learn to read before offering advice.
Maybe you should learn to write accurate descriptions before climbing up on your high horse and acting out all outraged and wounded.
As
@Iamchamps accurately described in two posts now, in order to fit a face plate socket, there has to be enough loose cable to allow a connection before the face plate or a grid module is secured in place. In other words, its impossible to fit a faceplate and leave no spare cable, or certainly not enough that a screw-on F plug can't be fitted. That's why your description doesn't ring true.
Now it seems like you're changing your original story so you can act the victim. That might fool some folk in other forums, but in this one there are several of us here who are professional installers. It's obvious to us when something doesn't add up.
How about we just start again? Why don't you tell us what's really going on. A picture would be tremendously useful.
You've added that the sheath is stripped back all the way past the back of the backbox. That in itself may not be a huge problem so long as the shield braiding is still covering the inner insulation down to the back of the faceplate. It's more of a problem though if someone has pig-tailed it so that the inner insulation and core conductor are no longer covered.
The other potential issue could be that the faceplate itself is unshielded.
From your description of how the cable is stripped, and from the collective knowledge and experience within this forum, that all points towards a bodge job. It could have been a DIYer with no clue, or an electrician who thought they knew enough but really didn't. Either way, this could be the red flag that points to other issues with the whole house install. The fact that you have signal changes and channel loss as you walk around the room kind of confirms that, don't you think?
Did you test the signal with a fly lead plugged in to the front socket on the faceplate before commencing with your plan for a Heath Robinson connection? If so, we're the signal loss problems evident then too?
Before we go any further, just look back at your thread. You have had good advice from the word go here, and some of us have taken a good chunk of time out of our day to write at length to help you. Now ask yourself, doesn't that seem like we know what we are doing and are willing to help?
It's up to you if you want to play ball. We can't make you take good advice from professionals and knowledgeable DIYers. The ball is very definitely in your court. What you do with it is entirely up to you.