I'd argue X is the most like VII. It tilted the series back into dieselpunk after IX turned away from it (and even technically takes place in the same universe, look it up) and its core cast is largely rehashing the VII characters, more aesthetically than writing wise, but even then. Tidus may be loud and obnoxious compared to Cloud, but he's got the same false memories about himself and mid-game twist connection to the big bad. Auron has Vincent's mysterious silent ronin in red shtick. Your token animal teammate is once again a native American inspired cat wolf. Rikku is literally just Yuffie, and Yuna slots nicely into Aeris's quiet, reserved nice girl whose fate is to die to save the planet. And I'm hardly the first person to compare Seymour to Sephiroth. Nomura's gonna Nomura.
As for XII, the game didn't even originally feature Vaan until somebody realized they forgot to add in the pretty blonde boy the franchise had become known for at that point. I haven't played XV so I won't comment on it beyond the fact that aesthetically it looks more like Advent Children than even VII does.