In general of course.
They are not, especially the new ones. You need to have special tools and knowledge to work on them and not so many people know about them (at least in the US).
Scotty addresses your question at 8:38 below:
Sorry, I can't read your reply because it was deleted with my answer. Can you write again?
Deleted answer:
https://www.autosmartmechanical.com.au/diesel-engine-maintenance/
What about the old 300D’s? Are those old enough to be easy to work on?