Standard Web-to-Case with assignment rules is a solution that can accomplish the requirement of allowing customers to log cases with structured data and route based on Urgency and Product Line. Web-to-Case enables customers to submit cases from a company's website using a web form that captures case information and creates a case record in Salesforce. Assignment rules can be used to automatically assign cases to queues or users based on criteria such as Urgency and Product Line. Verified References: :
https://help.salesforce.com/s/articleView?id=sf.knowledge_web_to_case_overview.htm&type=5 :
https://help.salesforce.com/s/articleView?id=sf.customize_caseassign.htm&type=5

Explanation
Defining criteria-based record page components is a solution that can address the issue of the Lightning Service Console being too crowded for service representatives. Criteria-based record page components allow administrators to customize which components are displayed on a record page based on certain conditions, such as record type, field value, or user profile. This can help declutter the console and show only relevant components for each case. Verified References: :
https://help.salesforce.com/s/articleView?id=sf.console2_components_overview.htm&type=5 :
https://help.salesforce.com/s/articleView?id=sf.console2_components_criteria_based.htm&type=5

Explanation
Creating a data category for each product and assigning data categories to service agents is the recommended approach to ensure that Knowledge searches only display articles for a service agent's product specialization.
Data categories are a way of classifying articles based on topics or criteria that make sense for your business.
Data categories can be used to control the visibility and searchability of articles for different users and communities. By creating a data category for each product, you can group articles by product line and make it easier for agents and customers to find relevant information. By assigning data categories to service agents, you can restrict their access and search results to only the articles that match their product specialization.
Verified References: Service Cloud Consultant Certification Guide & Tips, Data Categories Overview