Will vary from panel to panel, even in the same manufacturer's line-up. But in the accurate picture modes, I haven't had an OLED reach 900 nits, not even the GZ2000. But remember peak brightness measurements from windows is not accurate or representative of actual HDR performance.Not in any circumstances? The review I was quoting seemed to be saying 900 was the highest it could reach. I recall Philips claiming 900 as well.
Mind you manufacturers tend to falsely claim higher numbers.