I had to read and reread Hebrews about thirty times beginning to end over the course of about 20 days before I really began to fully grasp what the writer of Hebrews is saying. The entire book is a singular argument against what you’re saying @Pacman. Followers of Christ are not children of the bond woman and are not under the Law. We are saved by grace through faith apart from the Law, through the promise to Abraham. The Law was added later because of transgressions to be a schoolmaster to drive us to Jesus the Messiah. Those who are unsaved are under the Law which accuses them day and night, because they do not measure up. For a believer the Law tells us what good works are and the mind of God on matters such as marriage, divorce, kindness to neighbors, etc. Followers of Messiah are children of the free woman and are not subject carnal ordnances. That’s Hebrews in a nut shell.
I'm curious if you have studied the front of the book (specifically Deuteronomy) as deeply as you studied the book of Hebrews? Taking the whole context of scripture with you when you read the apostolic writings helps to avoid misunderstandings.