Interesting, I don't know much about "Nits" or the Samsung Plasma TVs.
My Panasonic TX-P55VT65B is also in a room with a 8 x 7 ft bay window.
I borrowed my brothers-in-law LG Oled, can't say it was that much better regarding the reflections?
The screen was brighter, but I found the whites a little bleached.
My other concern is, I could see "burn-in" at the bottom of the screen . He could see it too, but was waiting to see if I would notice it!
ATM I'm very reluctant to change to Oled.
Judging by your photo, that seems like an older model of OLED - my CX doesn't have the 'LG' logo at the bottom centre of the panel and I don't think the C9 or C8 had that either.
It's important to remember that LG and other manufacturers have implemented various features over the last few generations of OLED TVs including pixel shifting, logo dimming and pixel refresher, which all help mitigate the risk of image retention. And if you're coming from a plasma this is will all be old news to you as that technology suffered from the exact same problem. Presumably, you already know how to use your display sensibly.
In terms of the whites being 'bleached', well you can always adjust the settings or even get your TV calibrated.
I find the anti-reflection coating of the CX to be excellent and far superior to my old plasma, but the acknowledged market leader for anti-reflectivity is Samsung. Indeed the higher brightness of a QLED-LCD will give you a better image in daytime and a much brighter SDR picture than OLED so if those are your key concerns, you know which technology to plump for.
If you want an in-depth comparison between OLED and plasma this video by Vincent Teoh is very useful.