Which Final Fantasy Should I play?

Play VI--you love IX and VI is the game that feels the most like it, especially if you don't let every character learn magic.

Started playing FF6. If the game let me play with the magitek armor the entire time, I would have beaten it by now!

I'm playing 6 on the SNES Classic, I own the rest on PS4, so they have the fast forward options. The thing with Mass Effect, like legit.... I love them more than FF and find the Combat less repetitive. I know FF 6 through 9 aren't particularly long for JRPGs, but it will probably take me a month to get through just one of them. Just because I won't be able to do as big of chunks with them as I did with the ME games.

You can absolutely power level through FF6.

I wouldn't recommend going too far with it though until you've acquired Espers, because whichever Esper you have equipped will grant a stat bonus to that character on level up. +1 Magic, +2 Strength, etc. You gain access to Espers about a quarter of the way into the game. And since you'll be grinding anyway, you can go one step further with it and intentionally shuffle Espers around to grant each character the ideal bonus when they level up, depending on how you're wanting to build out the team. That's how I'd play it back in the day.

Magic is really powerful in FF6, so boosting magic power is probably "easier" long run than focusing on strength. There's an Esper called Zoneseek who you can get at the auction house in Jidoor, a town very near the place you first gain access to Espers. Zoneseek grants +2 Magic on level up, which is really really good.

Power leveling pays dividends all along the way, too, because FF6 almost always brings in new characters at the average party level. The stronger you are, the stronger they'll already be.

Edit: Also never put anything into or do anything to boost evasion, because the stat is broken. It literally does nothing. Magic evasion, however, is very powerful, because it works as both magic evasion and normal evasion.