Heads and horns are really important to establish. To do this, we go to Daniel and look at the goat and the ram in Daniel 8. The ram had two horns, and the goat had one big horn, but it broke, and four smaller ones arose in its place. In history, we know that the kings of the Medes and the Persians reigned together as the two horns. Alexander the Great was the large horn, and when he died, his four generals divided up the kingdom. Then, at the end of chapter 8, an angel describes that the heads are countries and the horns are people. In Rev. 17, it is talking about heads and describes them as kingdoms or countries that do not all exist at the same time. The beast that the whore is riding has existed for a long time. While Daniel 7 has several beasts, heads, and horns that exist at the same time.
We end up with heads being countries and horns being people. Using this, we can work out that the beasts of Rev 13 and Rev 17 are two separate beasts. We talk about

kings in the sense of being the heads of a nation. When Revelations talks about one of the heads suffering a mortal wound, it is talking about a nation that has had a mortal wound. Not a person.