This is a problem in Natural Language Processing and its tools for named entity recognition. For the first task, tokenization, the {tidytext} package provides the necessary tools.
Using stopwords to isolate names of persons is not the preferred method. For example, it could reduce Sheila Blanco to just Sheila. Stopwords are used to discard the common parts of speech, such as prepositions and conjunctions that have high frequency but low information content.
The usual way is to use a corpus of names of persons, institutions or placenames in a separate corpus. The {nametag} package does this for four languages but not Spanish. However, at the end of a GitHub repo several Spanish resources are given. NER