1) YIFY quality is as good as puke, mixed with mud, trash and then vomitted back out again by a zombie. If you're a movie buff, at least make an effort to get higher quality rips. Oh and btw, piracy discussion aren't allowed here.

2) The upscaling quality on my OLED C7 unit is not bad, a bit of ringing around the edges on some old content but generally it's quite good. IMO it's definitely good enough for most people. However, I use a HTPC and utilize MadVR upscaling using NGU, so upscaling on TVs doesn't really matter to me as NGU pretty much exceeds anything on the market as long as it's paired with a powerful enough GPU.

3)1080p content (I remux my own blu-rays, not YIFY quality bullshit) actually looks better on the OLED than being played on a native 1080p native display itself - which is in comparison to my old Sony W900a (arguably the best 1080p LCD LED TV, almost as good as Pioneer Kuro plasmas).

4) The best deals for C9 and C8 are literally just posted a few post above you. Like... really, you just need to scroll up once.