Get or Post SharePoint Online List using Modern Script Editor

I receive error 403 (FORBIDDEN) with Referrer Policy: strict-origin-when-cross-origin, while i make an Ajax request api call POST in SharePoint Online Modern Experience in order to put some data in a list.

I have tried plenty of times with different headers but nothing different happens except this error. 

My question is: -> Is there any chance to do this, via Modern Script Editor (except SPFX or Add in) in SharePoint Online Modern Experience or not?

Best regards

P.