Doctrine/dogma is an unchangeable truth defined by the Church. Generally they deal with the nature of things - Trinity, Incarnation, angels, man, original sin, sacraments, etc. Some deal with morals (abortion), but there are comparatively few regarding morals, simply because Scripture is so clear about what is morally wrong, and of course, Scripture is inerrant - so there is no need for the Church to issue a definitive statement.
“Fundamentals of Catholic Dogma” by Dr. Ludwig Ott is a good book which **lists the dogmas in bold print **with further info in smaller fine print. Great book for a Catholic to have as it gives the history around the dogma, Scriptural and early Church Father’s support.
Regulations have more to do with the way we practice our faith.
To give an example of the confusion. The Mass, it’s meaning, Jesus’ establishment of it and who can offer it, etc. are matters of dogma. The language, what readings, what type of music, vestments, incense …, all of that would fall under regulations and can be changed. They are external (to the truths about what the Mass is) and Our Lord did not mandate anything in regard to them (eg. altho external, the bread and wine were mandated by Jesus).
Code of Canon Law would be a source of Church’s regulation.
Not everything in the Catechism is dogma. A lot of it is “teaching” to present, illuminate, flesh out, etc a dogma. A dogma will generally be a single statement of truth - eg. "Jesus Christ is True God and True Son of God."
Now in the Catechism section on Jesus, you will find more than just that statement (and other dogmatic statements concerning Jesus). They will be explained; Scripture cited; thoughts or sayings from saints given.
It would be nice if the Catechism had incorporated statements of dogma in a very identifiable way - nice big bold red print. But you can and should read the Catechism and accept everything in it - and thank God for giving it to us.
Would appreciate correction if anything I’ve stated here is questionable.