I fixed this by adding the following JavaScript in my theme:
addEventListener("DOMContentLoaded", () => {
if (window.location.href.includes("?s=")) {
// You might need to use adjust the archive title selector
// according to the specific class of your header, for example:
// const archiveTitle = document.querySelector(".elementor-heading-title");
const archiveTitle = document.getElementByTagName('H1')[0];
if (!!archiveTitle) {
let text = archiveTitle.innerText;
text = text.replace("Search Results For: ", "Resultados de la búsqueda de: ");
archiveTitle.innerText = text;
}
}
});
This has disadvantage of creating FLUC (flash of un-styled content).