@adivj95 ,
Everything under /libs/cq/inbox/content/inbox is defined as jcr:mixinTypes = "granite:InternalArea", meaning these nodes should not be overlaid, inherited or used directly.
https://experienceleague.adobe.com/docs/experience-manager-65/deploying/upgrading/sustainable-upgrades.html?lang=en
This also implies that workitem menu or content page should not be modified.
Having said that, assuming if this nodes are not marked as granite:InternalArea, the below steps should help you out to create direct link to payload item from workitem page:
1) Overlay /libs/cq/inbox/content/inbox/details/workitem/jcr:content/actions to /apps and add a new node called "viewpayloadItem" with following properties:

This should show a new view payload action button on the action bar:

Then add this simple jquery script in a new author clientlib and making sure it is loading on the workitem page:
$( document ).ready(function() {
$(".inbox-details-workitem-action--payload").on("click", function name(params) {
var url = "/editor.html" + $(".foundation-layout-panel-body input[name=contentPath]").val() + ".html";
window.open(url, '_blank');
});
});
You may further improve this script by checking type of workflow payload item. If the payload item is a page then, prepend "/editor.html" or if the payload item is a DAM asset, then preprend "/assetdetails.html".
Just a thought.