I got my OP7P around launch time and the battery is at 88% now. So, not bad I guess?
IMO the battery is an area where OP devices show their true colors when getting costs down compared to more expensive flagships.
Of the half dozen or so OP phones I've owned, they've all degraded the same way at around the year mark: battery performance, USB port physically worn, some system performance issues, mainly apps seemingly not staying in memory as regularly.
On this 7P there have even been some periods of e treme sluggishness.