What took you so long?
Can't comment on FF7R since I haven't played it, I don't trust a thing that SE make to be any good these days, plus my PS4 is now officially a dust collector. Will probably still try it one day when it's on PC and isn't being sold in parts though.
As for what to play next, I'd highly recommend FF10. It's my personal favourite game of all time. It's got a great battle system, the best character progression system in the franchise and IMO the best minigame ever too.
FF9 is also great. I wouldn't rate it quite as highly as 10 (although it is close) and it's a bit more archaic given that it's a PS1 game, but it's still fantastic.