
Hi @Nanjappa, Ashwini,
I believe that this feature has been deprecated in modern experience SharePoint. But I think this can be replaced by a Power Automate flow which automatically creates a subfolder when a file is created or uploaded to a folder whose items more than a specific amount.
As this community is currently not supported Power Automate, I suggest you go to this forum: Microsoft Power Automate Community which is dedicated to it. Experts there will give you instant help.
Hope my answer helps. Thanks.
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