Falcon 10w horizontal problem

I’ve received a brand new Falcon 10w as a Christmas gift, i’m a total noob in cutting / engraving.
I made some engraving tests and i noticed what seems to be an horizontal movement problem

There should be a circle, which clearly comes out as an oval, and there should be an hexagon, which is not correctly closed and has curved sides.

I checked the rubber bands (both horizontal and vertical) and they seem to be stretched just right
I also checked wheels, there’s a slight bump when moving horizontal but i don’t think it affects the engraving: i get the same exact result even if i engrave it into another position.

I tested with both Lightburn and LaserGrbl

Any clue on what i’m missing?