If price and burn-in are not concerns, buy an OLED.
Otherwise get the EX750H now or wait for X9000F. Panasonic 2018 LCD switches to IPS panel in FX750 instead of VA panel in EX750H.
Sony has not announced X9300F for 2018 series. If this model is really killed, then both Panasonic and Sony are further downgrading the LCD product line in 2018. Both did not make the respective 2017 successors to DX900 2016 and Z9D 2016.