Just play Japan. Its braindead easy. I played 6 out of 10 placement matches as Japan and I won all of them. It was clear I was playing against opponents who were better than me in some of those games. I realized this while playing. They had better micro, they had to use much more APM for herding, they had their build orders practiced many times.
But in the end it didn’t matter, because I was playing Japan. Japan forces the other player to go out on the map and destroy shrines. If you don’t do this, you are going to lose. This is very taxing. And it can cause you to lose without realising it.
Ontop of this, Ashigaru are overpowered because they are too fast. 4.50 speed allows any Japan player to punish other players because their musketeers are faster. If you see 5 Musketeers attacking your shrines, send 10 Ashigaru and you will kill every single Musketeer. There is nothing your opponent can do other than sending an even bigger army. So you just send your army elsewhere. But spoiler alert, your army is faster. So you just outmaneuvered your opponent.
Japanese player are also extremely hard to punish. They can overextended with their Ashigaru and often times it does not matter, because Ashigaru can just run away form Skirmishers. The only thing thats faster is Cavalry, but they counter Cavalry.
Japan is an easy civ because of its design. The macro is also stupidly easy. If you do not macro properly, just click 1 button and have your shrines produce something else.
Japan also has an incredibly high skill ceiling. Once you hit Age 3 you can toggle your Golden Pavillion to give your units even more speed. This makes Ashigaru absolutely broken as they can outrun almost anything. You can raid with them, you can outmaneuver almost any army. And if you are a good player, just toggle the Pavillon to speed bonus or combat bonus whenever a fight is happening.
I have suggested to the devs to nerf Ashigaru to 4.25 speed so many times. But they will not listen. As long as Ashigaru speed stays at 4.50 speed, Japan will forever stay an easy civ, having the easiest micro and macro out of all civs, while still being very powerful with all around strong units and ugprades.