This should be doable without too much work, and no need to make extra tables.
First, make a new grid view on your [Tasks]
table (guessing the name) named “Due Soon”. In that view, create a filter based on your {Due}
field (guessing again), with the filter set to only show tasks that are within a certain range. For example, if “due soon” means anything three days out, the filter would look something like this:
As time passes, tasks that are 3 days from the current date will appear in that view.
In Zapier, make a new zap, and choose the Airtable “New record in view” trigger. After following the directions to connect to your Airtable account, you’ll choose that “Due Soon” view that you made. Going forward, any new tasks that appear in that view will trigger this zap. Old tasks that are still there won’t re-trigger it, only new ones.
From there, choose the email action that you wish to use to send your email (like “Email by Zapier”), and configure it appropriately. If you have further questions, don’t hesitate to ask!