My soul magnifies the Lord, and my spirit rejoices in God my Savior, for he has looked on the humble estate of his servant. Luke 1:46-48
For there is no distinction: for all have sinned and fall short of the glory of God, and are justified by his grace as a gift, through the redemption that is in Christ Jesus, whom God put forward as a propitiation by his blood, to be received by faith. Romans 3:22-25
If we claim to be without sin, we deceive ourselves and the truth is not in us. If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness. If we claim we have not sinned, we make him out to be a liar and his word is not in us. (1 John 1:8–10)
(Is this true? If you claim that Mary is without sin then you are saying God is a liar.)
You write this:
Scripture certainly doesn’t have a passage stating “Mary was conceived with original sin”.
But God's Word DOES say that "all have sinned" and Mary, blessed as she is, is included in that crowd.
Using your logic, you would need to find a "passage" that demonstrates that Mary was sinless. You can't do that - Luke 1:42 doesn't meet your need. Neither would any attempt to say that she was "full of grace" (Luke 1:28) and therefore sinless. That's a fail, too - unless Stephen was also sinless by the same description (Acts 6:8).
Finally, I won't be replying to you (unless you change your POV) because I've been in this rodeo a long time and even though the clowns are new - the act is the same.