You said, "The purpose of observing the holy seasons is not to incur favor with God, but to align our hearts with His by integrating the Gospel in our lives."
Claiming we need to "align our hearts" implies there are things WE can do to become aligned. That's not Christianity. Instead, JESUS "aligned" the world, reconciling us to the Father through His life, death, and resurrection. HE did FOR us, not dependent on our obediences.
We are SO misaligned, we CAN'T "align" our hearts to His. HE does ALL the saving, done by His love and grace! HE gets all the glory. It's not by our cooperating, either, such as "observing holy seasons." Jesus fulfilled those laws for us. Their purpose was to show us how much we can't keep them. This "alignment" is a "gift,lest no man boast."(Eph.2:8,9)
Better not read the Bible and apply God's Wisdom to our lives, lest we be guilty of attempting to boast. Better to leave the Bible untouched, sit down and let God do his stuff.
That's nonsense. We can choose to accept the gift of salvation, or to reject it it. By your logic, an unrepentant serial killer would be saved.