Sculpting Brush shape is oval instead of round

Hey community!

Hope this is the right section to post this …

Currently I am working on a figure I want to sculpt, but the
brush I am using seems somehow squished on the z-axis,
oval and distorted instead of round or the regular shape it has.
I tried it on an UV Sphere and it worked perfectly fine.

I attached an image of my object/sculpting for better understanding.

Have I done something wrong? I already tried resetting the brush,
but that didn’t do the trick. I build the figure via mirroring and finally
applying that modifier so it’d become one object to sculpt, is that
causing the troubles?

Sorry if there’s already a thread like this, but I couldn’t find
anything like this. Also sorry for the bad grammar and all,
english isn’t my native tongue.

In object mode use Ctrl+A / Scale to apply your object scale.

Look at your object scale values before and after doing this to see the effect