Is the interface, options and possibilities are a standard in every 3D programs.
Are my knowledge of the shader editor in Blender easily can be transfered to 3D max for example?
The idea of Nodes is not unique to Blender, but pretty much every program puts them together in their own fashion. The concepts you use in Blender may cary over to other tools, but the exact steps certainly won't.
Geometry nodes is pretty new to Blender, and still evolving relatively quickly. I believe it's roughly equivalent to Houdini SOPs, but I'd expect the workflow to be different between the two tools. If nothing else what a specific thing is called, and the shortcuts to do things, are going to be different.
When learning Blender, you'll have universal concepts in your knowledge tool belt that are transferable between any software. I'd say about 80% you learn you can transfer. Then there's a matter of different interfaces or new and different tools each software will have that you may have to readjust when changing software's.