In principle, you can use any USB-C power supply for charging. Preferably one that supports the PD 3.0 (Power Delivery) charging technology supported by the Pixel 7. https://www.digitec.ch/de...
You can use a power supply with a higher wattage. The smartphone will not be damaged by too many watts. It only uses as much as it needs. However, a larger power supply has reserves for another device or can charge two or more other USB devices at the same time.