Can I disable the delete list permission in SharePoint?
How can I customize the edit or contribute permission to remove the delete capability?
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You need to create your own Permission level in SharePoint according to your need.
Either you can create a new permission level from start or you can copy an existing permission level and make some changes like removing deletion capability.
Check below article:
Contribute permission is not having create list or delete list capabilities, Edit permission is having both capabilities, to remove those permission use following steps.