The 2 meter cable sold in the Google Store is the same cable that comes with the charger. As you found, it is out of stock.

I suspect this is the same cable, even though it says 1.8m instead of 2m length

https://www.amazon.com/Google-USB-C-Cable-1-8-Meter/dp/B01M4S095Y

This is a quality non-Google alternative. The key is to make sure you buy a USB-C cable that is USB-IF certified.

https://www.amazon.com/gp/product/B07RN3KCC6/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1