Hi @Aravinth Mathan ,
Welcome to our forum!
As i know, it's not available to up safe sender list via GPO in New Outlook for Windows. If you need the feature, i'm afraid that you need to switch to Legacy Outlook.
Please kindly understand that many functions are not designed at present. At present, what I can do for you is to submit feedback for your request and I have post here, and you could vote for it. If you have any suggestions or ideas, it's suggested that you could post here. Hope Microsoft will notice this in the future.
Thanks for your understanding and support!
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