Is there a way to automatically fill records in one table based off a tag in another table?

There’s a “Scripting Block” that allows coders to customize data movement like that. But I think your problems would better be solved by ‘views’ and ‘linked records,’ as discussed below.

I know I can use create a filtered view of the main Applications table to show only Funded groups, but I am trying to avoid convoluting that table too much

Views are how Airtable is designed to be organized. If you’re not dealing with too much data, you can probably get away with doing things however you like. But as the data set grows, views will be the better approach.

the Applications table is intended to track details related to the application process only, and I wanted to add and track different details for funded groups in another table

This sounds like it could result in creating data duplication and/or a lot of tables as the data set grows. ‘Applications’ is a good table name because each row of the table represents one application. If you ever find yourself creating a lot of columns for some other plural word (Groups for example) within the Applications table, then you may need to create a new table. Here’s a related base design article that breaks down some of these base design ideas. If you end up needing more than one table, I highly recommend learning about linked records.