Thanks for your work, there.
But the exegesis of Heb 4:1-11 in not in the context of the whole book of Hebrews.
The issue of the book of Hebrews is apostasy--falling away, departing the Christian faith, failing to enter God's salvation rest in Jesus Christ, the issue is not the Saturday Sabbath.
And to the issue of falling away, the writer brings the example of failure to enter Canaan (Heb 3:16-19, 4:2-3, 6, 11), the land of promised rest (Dt 12:9-10, 25:19; Joshua 1:13, 11:23, 21:44, 22:4, 23:1). Because they refused to enter, God closed the doors of Canaan in the face of a whole generation of Israelites (Nu 14:21-35). These NT Hebrews were facing a similar danger in their consideration of returning to their OT religion (Heb 4:2, 6, 11, 14, 6:4-8).
Hebrews reveals that the promise of entering God's rest still stands, but not in Canaan-rest, that door has been closed (Hebrews 4:3). It remains only in the spiritual Sabbath-rest of salvation in Jesus Christ, entered into only by faith in the person and work of Jesus Christ, not by one's own work. Salvation-rest in Jesus Christ is spiritual rest from our own work to save, and rest in Christ's saving work which saved us. It is into God's own Sabbath-rest that we are called (Hebrews 4:7-9) to enter (Hebrews 4:10-11) in Jesus Christ.
NT Sabbath-rest is rest in the salvation work of Jesus Christ, which these NT Hebrews were in danger of failing to enter, as at Canaan, by returning to their OT religion.
And not only would they not be entering God's Sabbath-rest in Jesus Christ, they would also be forfeiting the only sacrifice there is for their sin, rendering their hearts hardened and unable to repent, while crucifying the Son of God all over again (as the Jews did at Calvary--Acts 7:51-52) subjecting him to public disgrace (Hebrews 6:6).