how to change materials after render?

Hello guys, can u pls help me. I need to create 360 render for website with possibility of replacement textures and colors of some object, do i have to render 20 pics with like all colors or there is another way to make it faster?

If you want it to look accurate, then yes you should re-render each one since the bounced light off the colored walls will absolutely change the look of the room with different paints. If you value your time, then I would set up masks as a render element so you can edit the colours in post and save the different versions out that way.