Yes there are. If you want to pray the Liturgy of the Hours as the Official Prayer of the Church, the rules apply. That includes not skipping the hymns or any integral part of the Office.If you are a lay person, there are no rules. I skip the hymns. I also on pray antiphonal before and after psalms instead of after every verse like some do. And I will often just read and meditate on the readiness in the office of readings and not do Ny of the psalms or prayers as I do those in morning prayer!
If you want to merely adapt the prayer as private devotional prayer, then there are no rules, as one has always been free to offer devotional prayer anyway.
Praying the antiphons before and after the Psalms are the standard way to do it, except for the Invitatory psalm, which is normally done responsorially, but even saying the antiphon just at the beginning is fine in individual recitation. It does not “demote” the Office to devotional prayer.
As for the Office of Readings, if you merely read the readings and nothing else, then you’re doing sacred reading. That’s fine. But it’s not the Liturgy of the Hours.
The point is, if you want to pray the Liturgy of the Hours as the Prayer of the Church, then stick with the rules. Otherwise, let’s not make any pretenses that we can do whatever we want and still honestly say we’re offering the Divine Office. The Divine Office is the Divine Office only because the Church has declared it to be such, and in its approved forms.