Is automotive technician a hard career?
Just to preface, I am a mechanical engineer. But I know a lot of technicians in my specific field & know friends who work as engineers in automotive. I also have family who work with trucks and cars as technicians.
I read your question as "Is automotive technician a hard (real) career". If this isn't what you meant, please let me know as a comment. Thanks!
Short answer is yes.
As long as automobiles are around (which I would think will be a while)…automotive technicians will be needed. The only thing that may be changing is the topics covered in a certification program. I would speculate that the world will slowly transition more towards electrical cars. Hence technicians who specialize in gasoline engines, may have dropping demand as we transition to batteries and electric motors. But, the other components i.e. transmissions, differentials, braking etc will likely be similar.
In terms of progression, this really boils down to the employer. There is technicians who work for larger corporations, where they have a lot more training opportunities and progression. Some technicians may choose to start their own practice, where the progression is entirely up to yourself. Lastly you may work for a smaller local company, where the progression maybe significantly limited.
With that, I recommend trying to figure out what area of the automotive industry you want to pursue. Gotta start somewhere right? Maybe it's european cars, maybe it's diesel, maybe it's motorcycles, maybe you want to go straight to being a part of a race team...what ever path it is, you should look into getting ASE certified first. ASE certification takes the hardest part out of the equation which is getting even a small shop to pay attention to you and hire you, much less a larger dealer garage like BMW or Nissan.
Hope this helps!