I started fresh out of trade school, had mechanical aptitude and was thrown to the sharks in a Flat Rate shop first off. In that condition its sink or swim learn fast or leave, several did the latter. Being "Good" I likely do not fit the descriptor, took on any and all work I could sign up for in the early days, fought to make money learn everything I could, burnt out by 40. Still have my tools, STILL wrench on my own junk and have ceased with paying customers so my opinion may not be worth much.
You will need classroom training, paid for by Shop or out of your own pocket, the "Shop" you described sounds as half the small operations I had worked around where 80% of my practical time was in the dirt in the weather and OUTSIDE on site jobs. Shops were off and on but road duty was most profitable. I used to have manuals for nearly every machine I had to put a wrench to, many sold to those that followed behind me.
Whining not working enough skilled repairs does not cut it, know several guys spent two years cleaning sorting and inspecting parts to be presented to 15+year journeymen for the actual work. Same guys started Bottom Rung one rung up at a time where one now runs that very shop as Floor Foreskin. I traded the wear and tear, burnt out for a different career and stepped to retire a few years back, still wrench, still offer advice, still remembering where I came from and the sh!t I had to wade thru to get here.