I voted for Chrono, if only b/c it is the one series of the 3 to have a story continuity and gameplay (to an extent) identity.

I'm not too familiar w/ DQ, but I understand each game is its own story, perhaps w/ minor references here or there. Not sure how the combat or RP mechanics are throughout the series.

FF definitely has no identity besides chocobos, summons, sometimes moogles, and sometimes classes. Final Fantasy is basically Square's "our best effort RPG that we'll slap some summons or chocobos in." But no world continuity (besides spinoffs), no gameplay consistency, etc. I honestly don't really view FF as a real series anymore.

Chrono? Okay, it's not perfectly consistent. Different teams on each game (kinda like a variety of FF's and I assume DQ), and the combat and RP systems are way different between Trigger and Cross. But they're still in the same continuity, share some characters, have other shared tidbits like rainbow gear, a visually varied playable cast, Triple Techs, abstruse/obscure side quests that'd put FromSoft to shame, etc. Top-tier music (which to be fair isn't really part of GAME, moreso just happenstance of the composer talent). Even though it's just 2 games, it's an actual SERIES.

Plus, if we talk simple quality over quantity, Trigger and Cross are both highly rated to me. FF? I haven't liked a new FF (keyword "new", so counting launch FF14 and not FF14ARR) since FF12...17 years ago. So Chrono is 2/2, while FF is like 10/15, the last 3 being huge whiffs for me.