How to know who deleted few column in sharepoint list ?

Hi Bd2023-b​  I am not a Purview expert, but from what I can see, some activities related to list updates should be detected by this service:
https://learn.microsoft.com/en-us/purview/audit-log-activities#sharepoint-list-activities

To prevent some users from changing the list structure, you can assign them Contribute permissions instead of Full Control or Edit.