30 EUR per year? You can't even buy 2-3 liters of engine oil for that money, let alone brake oil, new tires (you change them every 50000km, right?), tire pressure sensors etc.
I spend 20 euro on the yearly oil change, including the crush washer. And about 10 euro on miscellaneous parts. A set of spark plugs were €9,28 last time.
Gear box doesn't need much. Oil gets changed when I do clutch, which isn't often. Just like how you don't need to change the differential or motor fluid on an EV motor often.
There's a 3rd cost that you're sorta glossing over. The work you're doing (and the speed you're capable of doing it in) means you've had a non-negligible amount of experience. Depending on how fickle we're going to get, there's 4th costs of the tools you own allowing you to do that work. Perhaps other costs for your living situation allowing you to have a place to do such tasks.
I do my own maintenance work too. But I think it's foolish to gloss over those aspects of the work. They don't come for free.