CROBUTKA

I am looking for HELP! New to 3D printing- got my ender 3 pro for xmas. I got the bed leveled very good . Good filament- sunlu,techbear,overature. I have a lot of stl files i have collected in anticapation of this adventure- I am trying to make clay cutters and on every one (from different sellers) The walls of the cutter have separation- enough on some that you can put a piece of paper in between them. The Picture shows my problem on a heart cutter . I think my problem is something i need to adjust in cura- can anyone help me.