If you look at Figure 1 at this link below you will find the visual acuity vs distance for a few different amounts of myopia. 20/32 is often considered the limit of good vision. As you can see the curve for -1.0 D intersects this acuity at about 3 meters or 10 feet. At 20 feet it would drop to about 20/40, the same as for longer distances. This is the limit in most jurisdictions for driving without eyeglass correction. So the short answer is that -1.0 would be marginally ok for TV viewing at 10 feet, and not quite as good at 20 feet. It depends on your requirement for sharpness of your TV image.
https://www.semanticscholar.org/paper/Optimal-amount-of-anisometropia-for-pseudophakic-Hayashi-Yoshida/dd8837a9151a536759f195a18d4fa94a0fbf0f90/figure/1
My experience with TV at about 12 feet is that it is very sharp with my -0.4 D eye, and a little fuzzy with my -1.6 D eye. It is kind of like watching standard definition vs high definition. At 20' you may something similar to standard definition if you have a HD TV.
Depends on the size of the TV screen too.
I view my 65" OLED TV from about 8feet away and get the sharpest most details view of HD/4K video with my eyes corrected for best distance vision.