Hello Omar 
That was If and but cases but check the below solution 

Solutions

1. Optimize Server Performance

• Upgrade Resources: Increase CPU cores, RAM, and disk speed (use SSDs).
• Load Balancing: If multiple users are active, consider setting up a load-balanced environment.

2. Review Custom Modules

• Audit custom modules or workflows for inefficiencies in their code.
• Optimize Python code and SQL queries in customizations.

3. Index the Database

• Add appropriate indexes to frequently queried tables (e.g., stock moves, stock picking).
• Analyze slow queries using Odoo's logs or database tools.

4. Batch Processing

• For operations with multiple lines, break them into smaller batches.
• Validate smaller batches instead of large operations to reduce processing time.

5. Disable Unnecessary Features

• Temporarily disable workflows like automatic reordering rules during bulk validations.

6. Technical Auditing

• Use Odoo's Profiler or log debugging mode to pinpoint bottlenecks during validations.

7. Upgrade Odoo Version

• Ensure you're on the latest stable version of Odoo, as newer versions typically include performance improvements.

8. Optimize Third-party Services

• If you use external integrations (e.g., payment gateways, shipping APIs), ensure they are not causing delays during validation.

9. Parallel Processing

• If you regularly process operations with many lines, consider scripting custom parallel processing to reduce load times.

I have version 16