High action is seen by some as a good thing, because it leaves the strings open to be strummed hard without fret buzz. Not saying you're wrong for wanting it lowered, but that you and Yamaha might differ about what your instrument is for, and so the solutions might be hard.
I cannot see the whole of the neck, but there should only be a slight curve, or relief; if you were to capo the first fret and fret the last, you should be able to barely slide a dime under the tenth fret, on the high end. There should be an adjustable truss rod where you can tighten it up to straighten it out and lower the action, either at the headstock or through the soundhole.
If your neck is good and the action is still high, the bridge is high. That might be because the belly is bulging or the saddle was cut high. You can sand down the bottom of the saddle to lower it, but otherwise, this is a question for a guitar repair shop.
Another issue might be that the neck might need a reset. This is because the string tension and other issues pulled the neck out of joint over time. This is definitely a repair shop issue, but this should be an issue for old guitars.
Solid-body electric guitars have an embarrassment of adjustable points, but acoustic guitars are pretty much as-is. "Take it to the shop" is pretty much my advice for you.
ETA: the "unplayable without capo" comment made me think that, additionally, the nut might need work as well, which is even more repair-shop work. I mean, I'm approaching 40 years of playing and never owned a nut file. But if you're having problems at frets 1-3, you're also likely having intonation problems as well.