It's always the same. People buy their used car for 20k used in cash/transfer, or for 30k new. The money disappears from the account, then the car is driven for 12 years, maybe still worth 10-20% of the purchase price. You don't have any "ongoing" costs for financing. Depreciation doesn't go directly from the account, that's why it's not there ;)
However, over 12 years (without considering inflation/interest/alternative investments),
the used car: 20,000 euros purchase minus 4,000 euros residual value = 16,000 euros depreciation, which is 111 euros per month every month, every year for 12 years!
the new car: 30,000 euros purchase minus 6,000 euros residual value = 24,000 euros depreciation, which is 166 euros every month, every year for 12 years!
What do you do in 12 years? Exactly, get rid of the car. What do you need then? Exactly, money :) So what do you do to be able to buy the car again in 12 years? Exactly, every month for 12 years you "save money" to buy the car. But that's not saving, it's simply "projected depreciation into the future".
So to save, say, 25,000 euros in 12 years (the vehicle now costs 29,000 euros (inflation, more technology etc), I get 4,000 euros from selling the used one, so 25k is still missing) for a used vehicle, you need another 173 euros every month, every year for 12 years.
Do you notice something - for a good used car that should last 12 years, just for the car itself (depreciation) and for the new purchase, you need about 300 euros every month. It won't get cheaper!
In addition, e.g. at least (!!)
insurance 40 euros
car tax 15 euros
maintenance & wear costs 50 euros (brakes, tires, inspection, check-ups) - 600 euros per year will probably only be sufficient in the first years.
So you have to calculate at least 400-500 euros per month for the car, no matter how you look at it. Anything else is undercoverage.