The first time, i tried creating a parametric model with this simple handle that have a m6 square nut inside the print.
You'll need a 6mm nut acc. to DIN 562 (low profile square nut) to be printed in.
You can for example get those from Amazon: https://amzn.to/3WoYLNO
During the print you need to pause at a height of 5.6mm (just add a material change in the slicer) insert the nut into the hole and continue printing. (make sure it sits as flat as possible)
I also uploaded my fusion 360 model that includes parameters. Feel free to play around with it. If you want to use a nut other than m6, there are no parameters for it, yet.
I created this model, but it was inspired from https://www.printables.com/model/832881-nutstein-parallelanschlag-bosch-gts-10-xc and also only created, because I had a lot of square nuts left over after printing it.
I use these to attach my https://www.printables.com/model/1103906-fibonacci-featherboard-with-variable-sized-feather to my GTS 10 xc as you can see in the last foto.
The author marked this model as their own original creation.