What is the optimal tire pressure for a Volkswagen T-Cross?

I recently bought a Volkswagen T-Cross and am unsure about the ideal tire pressure. The manual says one thing, but my mechanic says another. Can anyone give me some advice?

The recommended tire pressure for a Volkswagen T-Cross is typically 35 PSI.

I've been driving a T-Cross for a few years now and have found that 38 PSI works best for me.

I always aim for 40 PSI, it gives me a smoother ride and better fuel efficiency.