I wouldn't want my own children to have tv for a whole day every week.
Its not that its a terrible thing, the odd whole day if they are under the weather or you are or some other reason is fine. But every Sunday is basically 1/7th of their life.
I do think excess TV can cause children to not learn to get bored and find entertainment and can hinder development in many ways.
Children need a combination of exercise, downtime, outside and inside play, etc every day.
Maybe swap some cleaning to in the week rather than all at the weekend. i know it takes time, but maybe every evening after work you and dh do 20- 30mins together. Thats 60 mins x5 = 5 hrs of stuff that wouldnt need doing at the weekend. Tag team so one of you does laundry, one kitchen or whatever.
At the weekend it might be better to allow a fixed Tv amount say 1 episode sunday morning, and one sunday afternoon, and saturday evening 1 episode. instead of a bulk hours on end one day. Child then learns that they can see something, and then do somethign else.
If 3 year old doesnt like current toys, maybe he needs different types to what he currently has? Garden toys (wrap up and can go outside in winter), drawing and art stuff, maybe construction, puzzles or board games, den building etc. not all children like typical small toy play