It's really hard to say without knowing your circumstances.
The basic thing would be to look at the size vs the distance that you're going for and then consider things like brightness which could be an issue depending on the lighting in the room.
You could buy the 48" OLED but then need benolculars to get a decent view or get the 85" and need to physically move your head like it's a
plotter.
Also look at longevity, I think RTings has been running years long tests on TVs to see how long some may last.
That said, I plan on going OLED for my next TV after seeing on in a retail store, the difference was black and white between the LED next to it, although I'm hesitant to go for the cheaper model due to some concerns e.g. brightness as I believe the one I was looking at was dimmer than my current TV.
Maybe look for a retailer in your area you can browse in.