If Avraham or David is being written about then does that mean that Avraham or David sits at the right hand of G-d. Wouldn’t that make him equal to G-d? Can a man be equal to G-d? Because it says sit at my right hand?

Of course G-d can't be compared to man (Isaiah 40;25), the verse is metaphorically speaking, G-d is protecting David or Avraham as if they are sitting on his right hand.