Using a master list on one sheet for trackers on other sheets.

You can maybe achieve this in Excel for the Web using Office Scripts, which work in both the web and desktop versions of Excel.

function main(workbook: ExcelScript.Workbook) {
    // Define sheet names
    let masterSheet = workbook.getWorksheet("Master List");
    let pendingSheet = workbook.getWorksheet("Pending");
    
    // Define column indices (adjust as necessary)
    let statusCol = 4;  // Assuming "Status" is in column D (index 4)
    let clientIdCol = 1; // Column A (index 1)
    let lastNameCol = 2; // Column B (index 2)
    let firstNameCol = 3; // Column C (index 3)

    // Get used range of the Master List
    let masterRange = masterSheet.getUsedRange();
    let masterValues = masterRange.getValues();

    // Get table on the Pending sheet
    let pendingTable = pendingSheet.getTables()[0]; // Assumes there's a table on "Pending"

    // Loop through Master List
    for (let i = 1; i < masterValues.length; i++) { // Skip headers
        let row = masterValues[i];
        let status = row[statusCol - 1]; // Adjust for zero-based index

        if (status === "Pending") {
            let clientId = row[clientIdCol - 1];
            let lastName = row[lastNameCol - 1];
            let firstName = row[firstNameCol - 1];

            // Check if Client already exists in the Pending table
            let existingRows = pendingTable.getRange().getValues();
            let exists = existingRows.some(r => r[0] === clientId); // Check if Client ID is already added

            if (!exists) {
                // Add new row to the Pending table
                pendingTable.addRow(-1, [clientId, lastName, firstName]);
            }
        }
    }
}

Backup your file, Script is untested.

To make the script run automatically whenever the Master List is updated:

Open Power Automate.

Create a new flow with the "When a row is modified in Excel" trigger.

Set the trigger to monitor the Master List.

Add an action: Run Office Script and select your script.

My answers are voluntary and without guarantee!

Hope this will help you.