Force download with Js

I need to have a page that accesses two links, one in a window/tab that downloads a file and another one that after about 5 seconds or so accesses directly to this linl.

Currently I have the following code:

if ("URL1" !== '') {
    const link = document.createElement('a')
    link.href = "URL1" 
    link.target = "_blank"
    link.download = "pdf"
    link.click()



    setTimeout(function() {window.location.href = "URL2"; }, 5000 );

 } else {
     window.location.href = "URL2" />"
}

I've tried to force the download in several ways with Javascript since the tool I work with doesn't allow PHP, but I can't get it to download correctly.