Some of this is fair to tackle yourself. Reprogramming a remote, replacing batteries in a wall control, checking that the safety sensors at the bottom of the track aren't just knocked out of alignment - those are homeowner jobs and we'd rather you try them first than pay a truck to come out for a sensor that got bumped by a bike.
What we don't recommend doing yourself is anything involving the motor unit housing, the drive gear, or the high-voltage wiring behind it. We also won't tell you to disassemble a logic board to diagnose it - if you're not sure whether the fault is the board or the power supply feeding it, that's a multimeter job for someone who does it daily, not a Saturday project.
The honest limitation here: we don't stock every board for every opener brand on the truck, especially on units old enough to be out of production. If your opener is an older or less common model, there can be a lead time on the exact board, and we'll tell you that up front rather than promise same-day on a part we don't have in hand.