Here's the link to the similar question How to filter Data in dataTable lwc based on the input in search bar?

The above works fine with non-lookup fields but doesn't seem to be working in my case.

Edit : If I use regex.test(row.Name), I'm able to search the records based on Name column however, one of my columns has fieldName: Owner.Name and the search isn't working. Error: [Cannot read properties of undefined (reading 'Name')]

.js code snippet:

updateSearch(event) {
     var regex = new RegExp(event.target.value, 'i')
     this.data = this.testSearch.filter(
        row => regex.test(row.Owner.Name) 
    );

Any idea on above?