Pac-Man isn't so much representing himself, but more of Namco as a whole. He has many attacks that don't necessarily belong to him, such as Mappy's trampolines and Galiga's ship. But that doesn't change things. Pac-Man isn't top tier, but he is most certainly interesting. He's the kind of character that's hard to master, but when you do, it can be beautiful. I personally love playing as Pac-Man, but I'm far from mastering him. But I do know the Pac-Man meta, and to my understanding, here's what it looks like.
Pac-Man's moveset has a huge emphasis on his specials. As a matter of fact, most of your moves will be specials. His grab is bad, and his smash attacks aren't much better. But his specials give him all the tools he needs to create mass confusion. As Pac-Man your goal should be to launch an endless amount of projectiles to create confusion, and then go in yourself to limit your opponent's options. He doesn't have any spikes, and his nair and fair are bad at gimping, which limits your offstage options. But he does have an amazing recovery if done rights, so you can go in deep for what it's worth. It's important you use your side-B for recovery as its safer than his up-B. This also allows you to charge your neutral-B off stage for a very long time. His neutral-B changes as it charges, so sing its different properties can give you a huge advantage. For example, the apple and key can kill, the bell can stun, the Galiga ship can be used to wrack up damage and be used in combo with his down-B. Pac-Man's down-B is the fire hydrant. The hydrant shoots water which pushes people back, and once it receives enough damage you can send the hydrant flying, doing damage and killing if at at high enough percent. If Pac-Man can catch his neutral-B, he can juggle the item to damage the hydrant and his opponents to get them high enough to die from a key or apple. In short, you should be sending you hydrant and neutral-B around while attacking your opponents to deal damage, then finish off with a hydrant, apple, key, smash attack, and possibly a side-B.
This is just my opinion as to how to play Pac-Man, and I'm not actually that good at Pac-Man in comparison with others. Make sure you check other places for better tips.
When you hear me blow my horn, boys, make sure you charge!
-GIR