Selective Access Automation

I have a list using selective access. I want a user, from a new UX dashboard, to be able to add an item to the list then select some subset options then run a process to update the subsets.  The problem is that after the user adds the list item, they do not have write access to the new item therefore can't do any of the next steps.  Is there any way to automate so that when a new list item is added, a (or several) users automatically get write access? It's a flat list with no hierarchy so there isn't a parent to assign.  Thanks!