Hi,
You can do as follows:

1. Activate the developer mode
2. Open Settings -> Technical -> User Interface -> Menu items
3. Search for configuration menu
4. If you can see the menu here, see the assigned user group for the menu
5. Ensure your user is part of this group, if not add to it

Even if you didn't see the menu here, you can repeat the same by enabling super user mode.

For reference: Different Reasons For A Menu Not Visible In Odoo

Thanks