I discovered Goxel, https://goxel.xyz/, as a voxel editor and love so far. I recommend using it for getting into voxel art. It is simple and just works.
I could also export the project as an "obj" file for 3D printing :). The prusar slice could slice the obj file into g-code for printing.
On Linux I recommend using app image version because the flatpak version on Falthub is quite out dated at the moment of writing.