Using New Outlook on Windows for personal email, calendar, and contact management
Yes - same problem here - I can't rely on new Outlook to display any new emails sent to me - has been going on since I switched from the legacy or classic Outlook. Sometimes new emails appear within a minute, other times it's 4 or 5 hours or longer, and in the meantime I've been asking the sender to re-send the email. For me the issue only happens with Google email accounts - almost as if Microsoft doesn't want you using anything from Google!!
A fairly serious issue for an email application - not sure why Microsoft thinks it's acceptable to not fix this, or at least display an error message if there is an issue with picking up new emails from the Google servers.