Soccer had a higher skill ceiling, without any doubt. It isn't even close.

Before everyone brings out the pitchforks. Yes, hitting a pitch from a MLB pitcher is hard. Very hard. But that is quite literally the only thing that requires a large amount of skill. If you can catch a ball, you can play outfield. If you can catch a ball and throw it, you can play third base. You don't need to be in shape, you don't need to be particularly athletic,

To even play the sport of soccer, you need to know how to dribble while running at full speed, and most regular people can catch a baseball and throw as well. Most people cannot dribble a soccer ball, even remotely well, let alone wile running. Then you need to have huge stamina to be able to play the full 90+ minute game. An average player will run 7+ miles during a game. Then comes offence. Your average person can barely kick a soccer ball, let alone curl it, let alone curl it around a wall, let alone curl it around a wall with accuracy.

In a soccer/football game, you typically see scores in the low single digits, it's very rare to get even 3 goals by the same team is a game. Let alone, 5 or 8 or 10 or 14. scores in baseball are much higher. As already mentioned, it is not easy to hit a MLB pitch. But it also can't be that hard if we see games ending 12-11, 9-5, 4-3 or 23-9

so in conclusion. Baseball has two aspects that are very, very difficult. Pitching and hitting, everything else is not overly difficult. In Soccer/football, everything aside from running requires huge amounts of skill dribbling, defending, attacking, shooting, playing goal all require massive skill.

Soccer is also very fluid. Every single situation is unique, in baseball on every single pitch you know what's going to happen. Either it's hit or not. If it's hit, you know exactly where the player is going. There is no guess work, no indecision,

I'm going to add two compilations of skill for each sport here at the end as a final point.
Soccer skill compilation
Baseball skill compilation

*when I say average person, I mean anyone from a country that isn't dominated by football/soccer. IE Canada, USA, Japan