Create alert for all logged errors last 12hours

I want to create an Alert that runs once a day and send all logged errors (with specific filters) to a webhook.

I have created the alert, and the webhook gets triggered. So far so good. But this is for every 5 minutes for 5 minuten.

If I want to create a alert for my scenario, but I must setup; every 12h, en lasting for 12h. I want every 12h, lasting for 1second (or something).

Question how setup a alert to that runs once a day and send all logged errors?

Anyone?