That changes the width, I guess I should have specified fixed width

What is a fixed with, that is not a has not a fix value?

I mean elements with a width set in pixels, ems or some other unit. Setting width to 'fit-content' would override the width you set and then the element may overlap others to the right of it

Then you just do width: <width in ems> em; ? I thought you didn't want to specify a width.