de0u I think if you put the IMEI or the S/N into Google's warranty-repair page they will tell you the warranty date.
Exactly. The warranty check link should be this one: https://support.google.com/pixelphone/gethelp Have to log in to Google but the account doesn't need to be tied to the phone in any way.
For what it's worth, my Pixel 8 Pro had 0 cycles on it when I got it, checked while still on the stock OS with:
adb shell cat /sys/class/power_supply/battery/cycle_count
It's nice that GrapheneOS makes this easy to access (under About phone → Battery information), I think vanilla Android not longer exposes it through the UI.