Welcome to Android Central! Just get any respectable USB-C cable. There are dozens of them on Amazon and other online sellers. I've never had difficulties finding accessories for my Pixel. In fact, there are things for the Pixel that you won't find for other phones, like lenses and cases from Moment.
Never had that problem. There's the official cables from the Google store or Amazon. You can also use one of the many compatible non Pixel cables and chargers.
Don't forget your local stores. Cables are for sale all over the place.
If you think you haze to buy a specific Google branded cable to exactly match what came with the phone, you don't. Manufacturers will tell you to, but that's more a marketing thing than anything.