I’m sure they have the same goal of taking back the land they were kicked out of and keeping the land they have now, but the PA also wants self-determination and is more willing to compromise. Hamas is basically an off-shoot of the Muslim Brotherhood and does more terrorism while the PA is basically the more “official” representation of Palestine, currently led by Fatah, who have tried to resist occupation as well but are more open to negotiating peace with Israel. When they fought years ago, Israel secretly supported Hamas with resources to keep the conflict going and keep the Palestinians split up and weakened, so now Hamas has more control in Gaza and the PA in the West Bank. Israel also makes it hard to travel between the two, which also helps keep them split up and not unified.

While the PA aren’t super effective, that’s not really their fault. Try running a government without control of your own power, clean water, trash, trade, only allowed a certain amount of supplies based on the good graces of NGO’s that can convince Israel to go in, occasionally attacked by settlers or IDF soldiers who can do whatever they want, etc.

A 2020 documentary called Mayor shows the absurdities of trying to run a city without a functioning state. It’s about a Christian Palestinian mayor trying to do little things for his city while under occupation.