My take on reviews that state issues is that, unless every review claims the same, I assume some cross of user error or issue with that specific unit. Every Pixel I've ever owned has been crucified for having a litany of problems, and yet to date I have had virtually none (across Pixel XL, 2 XL, 3 XL, and 6 Pro).
Also worth noting that (to my knowledge) we don't know when the most recent updates were pushed out prior to release, so it could be that some users are having issues from not having updated or from having 3rd party apps they've installed that are not optimized properly and are causing contributing symptoms.
Hope yours is issue-free. I'm expecting mine to be, and will find out sometime tomorrow if FedEx stays on schedule.