sharepoint online – How can I add a link to a new item in List2 to an existing item in List1?

I work with two lists.

List1 is a list of clients with a column for client projects and other related columns.
List2 is a list of projects, with a search column that allows me to choose a client name.

Whenever I add a new item to the list of projects (List2), I want to add a link to this project item in the Project column of the client in List1.

I have created a workflow to start the item creation in List2 with one step to update an item in List1. In the Update List Item field, I chose List1, selected Client Projects as the field with Current Value: Project Name. I found the list item by customer and the value of the current item: customer.

When I create a project in list2, the workflow indicates that an error has occurred.

My intention is to be able to provide links to all List2 projects in List1 for each client, but I'm not sure where I'm wrong here. If there is a way unrelated to the workflow of linking these two tables, that would be fine too.