You’ve got everything going against you I am afraid.
You are starting with very low quality source (TV), making it look worse by transfering through those various stages and then not having the right software to compress.
Although you can’t polish a turd, it will help if you deinterlace the TV footage (I’m sure there’s an option for that in Premiere but it’s been a very long time since I used it). Other than that you are not going to make it look much better than you already have it except to tweek the brightness and contrast (get whites white and blacks black)
If you plan on making a business of this you really need to invest in some dedicated encoding software.
Video AllSorts