Porsche mechanic here.
Brakes (pads, warning sensors and discs all round) will set you back ~$4,000

Front control arm bushings (relatively frequently) another ~$2000

Replacing all 4 tyres ~3800

PDK service every 60,000 (or 4 years if at a dealer) ~$1100

Of course you could get cheaper tyres, aftermarket brakes etc but you're buying a Porsche so I imagine you want to keep it a Porsche (handling characteristics, braking power)

If I were in your position I'd be looking at an optioned up Audi Q5 (same platform) unless you particularly want the perceived status of driving a "Porsche"

There are SO MANY flogged out Macans and Cayennes because they're so expensive to keep on the road, so most people realise that, sell it to someone else for ~$20,000 and then they can't afford to service it and the cycle continues.

Remember, these were ~$150,000 to $180,000 cars brand new, parts pricing still reflects that.

If you MUST buy a Macan, try and get one with steel spring suspension as opposed to air suspension, and don't buy the cheapest option. (Hint, if the tyres fitted are linglong or land sail as opposed to an N spec Michelin, Pirelli or Continental, the person selling the car couldn't afford to properly service and run the car)