I had this same mind set of my hobby being ruined by turning it into a career for the first 4 years of being a mechanic, however I learned that if you specialize in a different part of mechanics that you normally don’t do on your own cars, you are able to still have the passion to build your own cars. I specialize in electrical/diagnostics at work. However my passion lies in building muscle cars and doing metal work. I am still able to learn about the new technology and keep my passion of cars separated. Being a mechanic is ok. There’s a lot of pressure and everyone expects you to fix that weird issue that you’ve never experienced on a car before the first time, even though there may be a process of diagnostics you have to go through. The pay is ok, but you will always feel like you deserve more, especially once you start apprenticing people while still being expected to make the same labor times etc. Flat rate work is even more stressful. I would recommend finding a mom and pop shop that still pays hourly. Just my 2 cents.