

Control software is not really used for any modern 3d printer, the printers provide their own web interface for you to control them.
Slicers just work out of the box for Prusaslicer, Orcaslicer and Cura. There’s nothing close to “compile your own kernel” in pretty much any linux thing anymore if you don’t want to do specifically this.
Okay, but changing the nozzle still is a normal modification that is required to do if you want to print abrasive filaments for example or thinner or bigger nozzle diameters. It’s very easy to change the nozzle because of that, manufacturers expect you to change it.
How about add-ons, not modifications? Do you count that as modifying if you add a raspberry pi or a camera, but you can still just remove them and have the printer just like it came ootb?