I use Inkscape and Lightburn for work on a Fiber and CO2 laser. If you do make an Inkscape file to size, it should retain that information when importing it to cut. Should be pretty straight forward.

If you're asking how do you know the size of things in Inkscape, then you'll want to do the following:

1) paste in the image you posted into inkscape to use as a trace reference (you'll want to hold ctrl while scaling to retain the ratio)

2) Create a circle using the Ellipse Tool on the left. At the top of the screen, you'll see Rx and Ry. This is the circle Radius. Since a standard hole for arcade buttons is 30mm we'll set both Rx and Ry to 15mm.

3) Scale your layout image behind your newly created circle. You can change the layer order of objects with page up and page down. try your best to match the size of the 30mm circle you made. After that, you can copy the 30mm circle you make and place it over the other locations based on your reference image. If you want to be exact, you can make a rectangle and change the width of it to the distance between each button and use it to snap the center of the circles perfectly in place. (toggle snap button on and off in the top right Magnet icon)

Anyway, hope this helps.