You could schedule a weekly automation to search for records with NULL values, but the problem is that after Airtable finds those records, you can’t do much with them.
For a no-code way of doing this, I personally recommend Integromat, which is a free automation platform (for up to 1,000 operations per month). It’s a very simple point-and-click environment. You don’t need to know any code at all, and they have full support for Airtable.
You can set Integromat to search your Airtable database for null values once per week, and then it can send out individual customized emails to the email address on each record that it finds.
p.s. I am a professional Airtable consultant and an Integromat Partner, and the Integromat link contains my personal referral code. If you have a budget for your project and you’d like to hire an expert consultant to help, please feel free to contact me through my website at ScottWorld.com.