Hi Patrick Henry,
Thank you for taking the time to share your detailed feedback regarding how Excel handles CSV files, particularly the automatic conversion of long numeric strings into scientific notation. I sincerely apologize for the frustration and inconvenience this has caused you and your business users.
I truly appreciate your feedback, I encourage you to share your experience directly with the Microsoft product team. Your input can help shape future improvements to the Excel.
You can submit feedback directly through the app by clicking on Settings > Help & Feedback > Suggest a Feature or by visiting the Microsoft Feedback Portal: https://feedbackportal.microsoft.com
At the same time, I kindly suggest raising a support ticket directly with Microsoft. Our dedicated support team has advanced diagnostic tools and resources that can help resolve this issue more effectively. You can raise a ticket by visiting the following link: Get support - Microsoft 365 admin | Microsoft Learn
Thank you again for your valuable insights. Please let me know if there's anything else I can assist you.
Best regards,
Chris-DKN - MSFT | Microsoft Community Support Specialist.