On Friday, I switched to the Pixel 7a with GrapheneOS and it's costing me CAD$1 per month for the phone on a 24-month contract and I got a better deal on my monthly phone plan. So far, it seems like an awesome phone and the installation of GrapheneOS via the web installer was incredibly easy.
That's a good question. I tend to plug my phone in whenever I get in the car, so unfortunately I don't have a good feel for battery life yet. I didn't notice an issue with my Pixel 6a, though.