Once they’ve gone that small, you won’t be able to save the quality. They will just become blurry. They don’t look much different than in the first ones size-wise. This is your cover so it’s your design and choices that matter. My input is just my opinion, so of course you don’t have to listen if you prefer your own.
To give an idea on a way to make the MC seem more significant in size, and to make the (I’m guessing, relationship) between her and the writer, seem more focal, I’ve made this mock up using some of my characters to show sizes.
Of course you can use more of the body to show arms etc in yours, but it’s for a rough idea. I also made the guy above, semi transparent so that he doesn’t dominate the scene.
