The best viewing distance for a 65-inch TV will depend on the resolution of the TV and the preferences of the viewer. As a general rule of thumb, the ideal viewing distance for a 65-inch TV with a 1080p resolution is about 10 feet or more. However, if the TV has a 4K resolution, you can sit closer to the screen without noticing any pixilation, and the ideal viewing distance would be between 5 and 7 feet.
Ultimately, the ideal viewing distance for a 65-inch TV will depend on personal preferences, but a good starting point is to sit at a distance that allows you to see the entire screen without having to move your head or eyes too much.