I haven't used the SEND EMAIL ALERTS WHEN RECORDS ARE CREATED/UPDATED on Saved Searches for a long time. I thought I remembered (and the field help seems to support this) that it should fire off an email within a minute or two if a record is added to the data set returned by the search. I can't get it to work though. I found a support article that said the search needs to be public and Send Emails according to Schedule can't be checked. Made those changes and it still won't work when I enter a record that will show up as a new line in this search. What's the trick here?

Just the obvious question - are you in sandbox?

Yup. But I turned emails back on; in fact I got a scripting error message (due to a testing script I forgot I had turned on) in my inbox when I first tried to create a record that would show up as new in this search. That came through fine, but the notification for the new record did not. I did try one quick in Prod and it didn't fire off there either.

Looking up in the slack archives -> Is there a reason why your criteria doesn't meet the create/update

Interesting. I haven't played with the Update Fields thing, thanks @Tim Chapman. I'll have to see if that's the issue. You must have super Slack perms to be able to go back in time. I only get 30 days back.🫠