How do I deal with being both operator and mechanic?

You can keep any machine alive, and you resent carrying two jobs in one body, running it and fixing it both. That resentment is fair. You are doing the work of two people and likely being counted as one. Naming that honestly is not complaining; it is seeing your situation clearly. The skill itself is a gift, even if the load is not. Being both operator and mechanic makes you rare and hard to replace, and that is worth something, in leverage if not yet in thanks. The problem is not your ability. It is how the weight is shared. So decide what to do with the leverage. Ask for the recognition, the pay, or the help that matches what you actually carry, and say it plainly to the person who can change it. If the answer is no, you will at least know where you stand. The resentment eases when you stop absorbing it in silence.