issue with selection / fill

Hello everyone, I'm going crazy trying to figure out how to solve this problem to speed up my creation process. In practice, whether I use the "magic wand tool" or the "lasso" tool, it's the same issue: I select the area, then use the paint bucket tool, and it fills the area while leaving a contour line, even if the tolerance is set to 200, and I've created the image on a new layer. I then have to go to Select - Modify - Expand, but it still creates a thin contour line. Even if that were to solve the problem, it's a time-consuming process. Can you help me? i have the last photoshop with updates and last OS and I work with wacom cintiq pro 16.