If there is a divine plan already set in place what is the point of praying?
The divine plan includes our prayers and free will choices.
If God already has a plan set in place for us our prayers won’t change anything if it goes against the plan He has for our lives.
Again, the divine plan includes our prayers and free will choices so that what God wants to give us depends on us asking him for it. We can ask God for various needs of soul and body and not only for ourselves but for others as well either living or dead such as helping the holy souls in purgatory. So, God has ordained in the divine plan that it is by our prayers that many things are given or granted to us and others and that without those prayers those many things are not granted.
We have free will but a plan for our lives is already set in place.
The divine plan includes our free will choices which also involves prayer by which we are better off if we follow God’s will and commandments or worse off if we don’t. Will prayer change anything? Yes, because God has ordained in the divine plan that through prayer not only ourselves can be changed or converted but by our prayers we can help others too toward conversion.