10 for sure, as I've tried multiple times. Sadly, my first playthrough ended right before the last stretch. I had no motivation to continue. I tried again when I got older and found myself even less interested and barely made it past Rikku joining the party

I've had similar experiences with 8 and 9, though I don't hate them as much, but would probably likely yield similar results. I just don't like them enough

12 is a rare case where I thought I felt similarly about it, but then thoroughly enjoyed it my second playthrough almost 10 years after it came out. Unfortunately all of our PS2s started to act up, and then the re-release on the PS4 happened. So I found it hard to justify giving myself that much of a headache over it when I could just replay it more conveniently and with a better version on a newer console. I've yet to restart, but I have faith that I'd likely finish it when I do

And since we're counting side games, FFT is definitely in there. I've tried maybe 3 times with that game. But it embodies everything I hate about modern tactical RPGs, especially those from Japan (Look at Fallout 1 & 2, and Divinity: Original Sin 1 and 2, and Torment: TIdes of Numenera. Towns to explore, people to talk to, and your character(s) have agency withing the world and the story). Nothing but battles and story sequences. And a lot of grinding. Which makes it even worse. Which is too bad, because outside of Fire Emblem, it's one of the only tactical JRPGs that doesn't have a battle gimick with colored squares or some similar garbage

I think I would struggle with FF5 as well. It's hard to appreciate the characters when a lot of their mannerisms are just tropes and comedy schlock. I never felt any gravity or investment the couple of times I tried the game. I need to do a modern replay of FF4, 6, or 7, and see just how well they hold up to my nostalgic scrutiny. Maybe I'm just not a vintage JRPG fan anymore. But at least those hold some fond memories. I'm honestly surprised I've beaten FF1 multiple times since adulthood since I was like 6 when I first played that game, and it's still fun, for a lot of variable reasons, and surprisingly easy to just knock out over a couple of days