What's in a word?
The Merriam Webster online dictionary defines "free will" as:
1 : voluntary choice or decision
I do this of my own free will
2 : freedom of humans to make choices that are not determined by prior causes or by divine intervention
The emphasis is on choice and decision.
However, the same dictionary defines "freedom" as:
1 : the quality or state of being free: such as
a : the absence of necessity, coercion, or constraint in choice or action
Here we have absence of necessity, etc., in choice or action.
The distinction between freedom of choice and freedom of action is critical to answering the question.
But first, why bring "freedom" into it when the question is about "free will"?
The Bible promises freedom, not free will
Search the Bible for "free will" in any of the commonly used translations, and you will come up empty. "Free will" is not a biblical term.
However, search for words such as "free," "freedom," "liberty," and there will be many hits, both in the Old Testament and in the New Testament.
What the Bible speaks of and promises us is not "free will," but freedom. To quote one key example:
Then Jesus said to the Jews who had believed in him, "If you continue in my word, you are truly my disciples; and you will know the truth, and the truth will make you free."
They answered him, "We are descendants of Abraham and have never been slaves to anyone. What do you mean by saying, 'You will be made free'?"
Jesus answered them, "Very truly, I tell you, everyone who commits sin is a slave to sin. The slave does not have a permanent place in the household; the son has a place there forever. So if the Son makes you free, you will be free indeed." (John 8:31-36, NRSV)
There are many more instances. See, for example, Psalm 119:45; Isaiah 61:1; 2 Corinthians 3:17; Galatians 5:1-15.
It is important to understand that though we may speak of "free will," what the Lord actually promises us in the Bible is that if we follow God's way, we will be free.
Freedom of choice vs. freedom of action
Now let's consider the critical distinction between freedom of choice and freedom of action.
The question as asked dwells largely on freedom of choice. Specifically, it focuses on the freedom to choose between good and evil, or between between righteousness and sin.
However, freedom of choice is not the only kind of freedom. And ultimately, it is not the most important kind of freedom.
Yes, it is important for us to be able to choose between different possible courses of action, especially including good and evil courses of action. But what meaning does this freedom of choice have if, having made the choice, we are not free to act upon it?
Freedom of choice is our primary freedom on earth
Spiritually speaking, here on earth our primary freedom is the freedom to choose between good and evil, between righteousness and sin. The Bible continually lays this choice in front of us. Making this choice is our primary "labor" during this earthly lifetime.
However, we may or may not have the freedom to act upon our choice. Legal, social, and financial strictures limit our freedom of action in many ways. We can act on some, but by no means all of our choices to do good, or to do evil.
Freedom of action is our primary freedom in heaven
In heaven, that order of freedoms is reversed. There, our primary freedom is freedom of action. Why? Because by the time we reach the afterlife, we have already made our choice between good and evil. If we enter heaven, we have chosen good over evil.
In fact, one of the freedoms of heaven is the freedom from the fear of losing salvation. Christians have debated "once saved, always saved" for many years. By the time we get to heaven, that debate is settled for us. There, we have "rest from our labors" (Revelation 14:13) of fighting the battle to choose between good and evil, salvation and damnation, that commonly consumes us here on earth.
The primary freedom we have in heaven is the freedom to act upon the choice for God, and for good, that we made during our lifetime on earth. There, we are no longer constrained by external legal, social, and financial strictures from acting upon our choice to live a life full of the love, goodness, and truth that come to us from the Lord.
Even in heaven, we can still make choices between different courses of action. But our choices will always come from a heart filled with the love of God and the neighbor. We will therefore never choose to do evil.
However, the key point to understand is that although we have already made the "big" choice between good and evil, and therefore don't have that particular freedom of choice as we did on earth, we have the far greater freedom of being at full liberty to act according to the choice we have made to accept and live by God's love.
Further, the lack of freedom to choose evil to eternity is no real lack of freedom at all. Rather, it is a lack of danger of falling back into slavery. And when we are living in heaven, choosing to do evil is the last thing we would ever want to do. As Jesus said:
Everyone who commits sin is a slave to sin. . . . So if the Son makes you free, you will be free indeed. (John 8:34, 36)
This answer is written from a New Church, or Swedenborgian, perspective.