Using New Outlook on Windows for personal email, calendar, and contact management
The type of account will decide how often new e-mail is retrieved from the server, as I am sure you already know. Exchange accounts are synchronized once per minute, according to https://support.microsoft.com/en-gb/office/sync-basics-what-you-can-and-cannot-sync-5537d587-4930-4ac2-b044-3568509b1294. The New Outlook has no additional options for this at the moment. The feedback portal is at https://feedbackportal.microsoft.com/feedback/forum/89a8afa3-2e1c-ec11-b6e7-0022481f8472.