Yur presume that we Calvinists don't belive in Free Will. Perhaps you should stop looking at us through the lens of Catholicism and Arminianism.
Here’s the explanation: men can accept or resist grace according to their free will.
Yup. That is what we believe.
But there is one important Scriptural part that you are overlooking. In our fallen state, our free will chooses not to accept God's grace. We don't want it, aren't interested.
When God regenerates us, through the Holy Spirit, our free will longs to come to Christ. we begin to abhor our former selves and willingly enter into a salvific relationship with God though Christ.
And that my friend, is found in every book of Scripture.
God’s love is unconditional and extends to the reprobates (those who don’t love God back).
In so much as he allows them to live a life here and now that is the best they will ever have, yes he does.
The "free will" you describe here is not free will at all.
You yourself explained in the same post what is it that you believe, proving my presumption.
In our fallen state, our free will chooses not to accept God's grace
Not always. Mary accepted it; St. John the Baptist, the Apostles at various times, St. Stephen the First Martyr, and all the canonized saints, plus countless uncanonized ones, plus the Old Testament righteous starting with Abel.
There are exceptions but most people I regularly see at Mass are there because they freely accepted the sanctifying grace.