Hi Andrew •,
Welcome to Microsoft Q&A forum and thanks for using Azure Services.
As I understand, you are unable to import excel data using Table Import Data Wizard which is taking long, and not complete data imported.
This seems strange and should not happen. Could you please let us know if you have checked all network or connectivity aspects of your server?
If not, we recommend you to check and retry.
Refer https://learn.microsoft.com/en-us/azure/mysql/single-server/how-to-troubleshoot-connectivity-issues
https://learn.microsoft.com/en-us/azure/mysql/single-server/how-to-troubleshoot-common-errors
If this does not help, please let us know for further investigation.
Thanks.