InvocableMethod for updating grand child records in Salesforce Process Builder

UpdateGrandChildRecordsAction.cls

public class UpdateGrandChildRecordsAction {
    
    private final static String TARGET = '{0}';
    private final static String REPLACEMENT = '\'\'{0}\'\'';
    private final static String FORMAT = 'SELECT Id, {0} FROM {1} WHERE Id = \'\'{2}\'\'';
    
    @InvocableMethod(
        label='Update Grand Child Records Action'
        description = 'Query child and grand child records and then update grand child records'
    )
    public static void updateRecords(List<Request> requests) {
        
        for(Request request : requests){
            processRequest(request);
        }
    }
    
    private static void processRequest(Request request) {
        
        String queryString = request.queryString.replace(TARGET, REPLACEMENT);
        
        queryString = String.format(queryString, new String[]{request.filterValue});
        
        List<sObject> childRecords = Database.query(queryString);
        
        for(sObject child : childRecords){
            
            queryString = getQueryString(request.objectName, request.fieldName, (String) child.get(request.childFilterField));
            
            List<sObject> grandChildRecords = Database.query(queryString);
            
            if (grandChildRecords.size() > 0) {
                SObject grandChild = grandChildRecords[0];
                grandChild.put(request.fieldName, request.fieldValue);
                update grandChild;
            }
        }
    }
    
    private static String getQueryString(String objectName, String fieldName, String recordId) {
        List<String> args = new String[]{fieldName, objectName, recordId};
            return String.format(FORMAT, args);
    }
    
    public class Request {
        
        @InvocableVariable(
            label = 'SOQL Query'
            description = 'SOQL Query with {0} for the filter value'
            required=true
        )
        public String queryString;
        
        @InvocableVariable(
            label = 'Filter Value'
            description = 'Value used to filter the SOQL query'
            required=true
        )
        public String filterValue;
        
        @InvocableVariable(
            label = 'Child Filter Field'
            description = 'Child Field from the SOQL query to find record to be updated'
            required=true
        )
        public String childFilterField;
        
        @InvocableVariable(
            label = 'Object Name'
            description = 'The name of the object with the field to be updated e.g. Account or Custom_Object__c'
            required=true
        )
        public String objectName;
        
        @InvocableVariable(
            label = 'Field Name'
            description = 'Name of the field to be updated e.g. Name or Custom_Field__c'
            required=true
        )
        public String fieldName;
        
        @InvocableVariable(
            label = 'Field Value'
            description = 'Field value to be stored'
            required=true
        )
        public String fieldValue;
        
    } 
}