Let's say I want to render a music video with a still image on it (1920x1080) resolution, and I know if I were to decrease video bitrate, the image quality would deteriorate, how about if I would increase it to a very big amount, how that would affect the quality?
If you choose a high enough video bitrate, the quality of the image rendered as a video will make the image appear just like the original. In other words, at some (high enough) bitrate, you will not perceive a difference between the original image and the video version of it.
Of course, mindlessly increasing the bitrate will not get you any "better" image, and it will just waste storage space and transmission bandwidth. But coming back to your question, increasing bitrate will never make the image look worse.
What that target bitrate is, I cannot tell you. No one can: it depends on how complex the image is to encode. You just have to try.