Scaling Up character without pixelation

I made a character originally in Illustrator but I was having issues with it and put it into Photoshop. So, I have a Vector version of the character. I made the character at 1080p, without thinking about the fact I was going to have to scale up the character in the scene, so now I have a pixelated version of the character. I optimistically thought I could re-make the character in an 8K photoshop file and switch it out within Character Animator but sadly it didn't work as all the handles and everything stay in their original position. Does anyone have any advice on whether this is possible? Sorry if I've not explained this well. Happy to give any further details if necessary.