Yes, it is. I mean, GrapheneOS is the gold standard for privacy&security, but even stock Pixel is a good step up. Think of it like this: on stock Pixel, only Google is tracking you, not Google + Samsung, or Google + Xiaomi. Just Google. It’s guaranteed to be a step up from all other Android phones, stock or not.
I discovered privacyguides.net. good website.
Yes. A Pixel Tablet was released recently. GrapheneOS (a good privacy-focused custom ROM) supports it too. And iirc the tablet supports USI2.0 stylus. But it’s 500$ US brand new