Oleds in general will take time getting adjusted to, but after you start liking the emissive technology, you can't turn back to LCDs. Lg C1 and A80J comparison in vivid settings is like comparing football players wrt their cricketing skills.
1) You must avoid vivid or bright room settings
2) Compare asking them to show you a blue ray movie clip in home cinema settings
3) ask them to put a content your family might watch often and compare that to an LCD! 77" OLEDs will cost you a ton and yet might not be appealing to those who don't agree black is beautiful. Plus they could rough use the TV.
What is your budget and what content do you and your family watch? 85" TVs are also something you may consider. What's the viewing distance? In my humble opinion, 77" screens will offer reasonable price in a few years due to supply and demand logistics and it will soon emerge as the current 65" OLED pricing. As humans push the bar in electronics as time progresses, right now it is a year and a half early I must say, it would come to 2.5-2.75 in a year and a half. So would 85" LCD screens from the big three.