I think the bottom line is that we need to follow scripture. God is eternal, God principles never change, and as Christ told us, He did not change anything.
When we read in the letters how there was "change", we need to read that in spirit and truth. We have a high priest. There was a high priest that Moses told us of, and the functions of a high priest never changed. If we read about a high priest in the time of Moses, and we read of our high priest today, they are both the high priest with many of the same functions. Christ is our high priest. That is the only change.
When you read of the functions of the Sabbath at creation, and you read of the functions of the Sabbath when Christ plucked grain and healed on the Sabbath, it is all the same from our eternal God. Christ made it clear.
The Old Testament was written in Hebrew, using the Hebrew people to explain God. They were an emotional people who had no words for their emotions, but when they felt something they thought of the acts that emotion would bring about. Loving the Lord brought actions of love for the Lord. When a new kind of thinking entered, it had to be explained to us that an emotion needed action to be authentic, that faith without works is dead. That direction would never be needed before the Greeks influenced thinking, for action and feeling was ingrained in their way of thinking.
So we say that the actions spoken of in the Old Testament are without meaning. And when Jews advanced to become Greek thinkers, some of them DID use actions alone.
These things happening in the world did not change God. God's thoughts are above our thoughts. We need to put on Christ (who is one with the Father) through the Holy Spirit we have been given, and rise above these worldly, fleshly interpretations of God principles.