Duplicating animations on multiple Illustrator compositions containing multiple in After Effects

If just the text is changing, you can animate multiple text layers in one Composition (either as Text Objects in the Illustrator document or After Effects Text Layers).  Once the animation is designed, show the first text layer(s) and send the Composition to Adobe Media Encoder (AME).  Then show the second text layer(s) and send the Composition to AME again.  Then show the third text layer(s) and send the Composition to AME again.  Repeat until each variation has been sent to AME.  In AME, set the Format pop-up menu and Preset pop-up menu as needed and set the file name such that it easily differentiates each render.  If you prefer to use the After Effects Render Queue, you'll have to render the Comp immediately after adding it to the Render Queue, then change the text layer(s), and queue the Comp again to the Render Queue and render it, repeating until all the versions have been rendered.

If the artwork needs to change after being animated (not just the text layers) that's a little more involved.  One approach is to use File > Replace Footage at the the Project level.  Or, import the second Illustrator file with different artwork but same animation, duplicate the first Comp, then use the option/alt drag and drop to a selected Layer to replace the Layer Source one at a time.  If the file name and layer names of the second Illustrator file are exactly the same as the first, the second file could be swapped out at the Finder/Explorer level while the After Effects project is closed - but be very cautious about not accidentally overwriting the two Illustrator files that are different, but have matching file names.

There are options for using a spreadsheet with After Effects as well as using Essential Graphics to design After Effects Text Layers once and easily edit the Text Source in duplicate Comps.  That's not difficult, but is more advanced, and may not be worth switching to if the Text Objects are already made in a Illustrator file.