In xpath/xquery builder in oxygen:
set xquery 3.0

declare default element namespace "http://www.tei-c.org/ns/1.0";
let $names := for $n in //persName/string-join(descendant::*/text()," ") return $n
return string-join($names," ")

returns just the texts.

The equivalent in the xpath box above the editor
//persName/string-join(descendant::*/text()," ")

returns the strings, but also the system id etc for each that you then have to manually delete