Yes. What you say is true.
However , a problem comes in for many in today's church though because they follow a flawed logic. The logic goes something like this. Take as an example , our responsibility as a parent. Premise ....we are not saved by being a parent to our children. Conclusion... we will be in works and not in faith and lose our salvation if we parent our children. This logic is systematically applied to every command that God gave and thus becomes lawlessness in practice. This bizarre view that God somehow uses " reverse Psychology " on us by telling us that we do not have to do anything is very dangerous to the spiritual life of many in today's church. Some even take it so far as to suggest that things like prayer and fasting are works and therefore wrong for the Christian.
Dividing the law into ceremonial and moral aspects helps to minimize and bring some sanity to the issue.
I would also point out though that there is also a divide between those parts of the law which were intended to cover sin such as animal sacrifices versus obeying God's commands about the Sabbath. The Sabbath was never intended to forgive or cover sins and that is the main issue when we speak of trusting the law for salvation. There is the issue of obedience to God's commands and disobedience is sin. But the covering for sin was not to do the commands , it was the sacrificial system.
When we speak of the context of scriptures such as the letter to the Hebrews and Galatians , we need to understand that the context was Jewish Christians making animal sacrifices for their sins and also coming under the authority of the Pharisaical Jewish system. The circumcision was not just about performing a ceremony. It was and still is a conversion ceremony which says that a person is identifying themselves as under the Jewish system. Paul's objections were more than just an objection against a ceremony. He recognized the significance of placing ourselves under the spiritual authority of the Jewish leaders. This meant an acceptance of The Old Testament and also the traditions of the Jewish leaders including , at that time , animal sacrifices.
If I showed up for church next Sunday and some were offering animal sacrifices to cover their sins just in case Jesus was not enough , I would be confronting that just like the Apostle Paul did. We need to understand the context was not a North American Jewish Christian deciding to keep the Sabbath.
As you pointed out , the moral law still stands and it is also debatable as to whether all of the ceremonial law is done away with. As you have pointed out in some of your other posts , the Hebrew thinking is multiple fulfillment of things and not just a linear Greek model of either or. It is possible for Jesus to fulfill things and still have other purposes in those things. Take communion as an example of this.
It probably isn't much of a secret to those familiar with me or my posts that I don't accept the standard protestant/evangelical soteriology (doctrine of salvation). Though I was raised with those ideas and teachings, and I believed them well into my adult life.
I can remember even when I firmly believed the protestant doctrines in this area, there were a number of things that simply didn't make sense either logically or Biblically... but I accepted it because I had faith and I assumed that either I was just thinking wrong, or there were things I hadn't learned yet that would eventually make sense of it all.
One of the things that didn't make sense to me was that on the one hand protestant doctrine clearly taught that we were not saved by works and yet the New Testament routinely says that God Judges people by their deeds. To my knowledge, every description of final judgement in the New Testament, including those given explicitly to Christians, say explicitly or strongly imply that we are all going to be judged by our deeds. There seems to be a clear disconnect between the scriptures and the teaching there.
Another thing was similar that the New Testament routinely emphasizes the absolute necessity of obedience and bearing fruit, yet protestant doctrine always taught that we were saved without obedience and without bearing fruit etc.
For a while I considered Calvinism because it was more logically consistent within its own doctrines, but eventually I came to the conclusion that while it was consistent within itself it had two problems. First it contradicted scripture explicitly and in those instances required interpreting scripture in ways that I did not think were consistent with the text. In other words, their doctrine was consistent, but I didn't think the Bible itself was consistent when forced into the Calvinist framework of interpretation.
Lastly, and most recently I came to the conclusion that the doctrine of Penal Substitutionary Atonement, which is the absolute foundation of much of protestant soteriology and related doctrine, is fatally flawed.
This is one of those objections I had long ago but I dismissed it because the doctrine seemed to foundational to my faith. More recently I came to understand that it is only foundational to protestant and particular Calvinist and some Lutheran doctrines.
In fact, PSA doctrine is essential to some protestant doctrines of salvation because it is needed to justify exactly the problem that you are talking about. You can't have the attitude and the idea that you are talking about without PSA.
My point regarding the ceremonial aspects is that all of those things were given in the Old Covenant to be types of or almost prophecies of things that were going to come under the New Covenant. Circumcision, for example, is a type that foreshadows and foretells baptism. The Passover Feast is a type that foreshadows and foretells the Communion Feast.
While I don't think it is objectively wrong to circumcise, or to observe passover, there is a danger in the propensity of some to value circumcision over baptism, or value Passover above Communion. In doing this, in my opinion, they are replacing the New Covenant with the Old.
I do agree that the ceremonial aspects continue, but I believe that they have been renewed and transformed. They are part of the New Creation, just like we are. God said, for example, that the Passover sacrifice would be an eternal ordinance. The feast would be observed forever. This has been fulfilled beginning with the Last supper, culminating on the Cross on Calvary, and continuing in the Communion. Christ's Passover sacrifice is perpetual and is perpetually being celebrated both on earth in the Communion and in Heaven as Christ offers it in the temple in Heaven.
I don't have a problem with observing a Saturday Sabbath if you want, but I think the same danger exists in failing to see the fulfillment of the Sabbath in Jesus Christ and his New Covenant. It is not that the Sabbath came to and end (as with Passover) but the old type has been fulfilled and transformed into its eternal form in the New Creation.