Fix the hreflang tags of my website

My website is based on Wordpress and when accessing to the homepage of the default language which is Spanish it redirects to the homepage of English language. After testing with [login to view URL] and other tools it reads there is a 302 Found Status and that the page is not indexable. Also, the Hreflang X-Default is not set for the pages. I am using Polylang plugin. It is a very small website of only 14 pages. Also, I would like to check that all the pages without trailing slashes at the end of URLs are correctly redirecting to the pages with the trailing slashes at the end. I need the change to be done in a way that when Wordpress, the plugins or the theme is updated the Hreflang tags will remain working correctly. Thank you and waiting to hear from you