Animate size of each letter in text with effector

I'm fairly new to Blender so this might be a really simple question. I want to animate each letter in a text with an effector (different shapes and patterns) in a similar way to these references:

https://studiodumbar.com/media/pages/work/amsterdam-sinfonietta-identity/1549645332-1586263695/as_case_motionsinfonietta_intro.mp4

https://studiodumbar.com/media/pages/work/amsterdam-sinfonietta-identity/1331194541-1586263695/as_case_andriessen-moore_detail.mp4

The closest I've come to any tutorials is this: https://www.youtube.com/watch?v=LtKmb4E7CuY&ab_channel=BlueFoxCreation but I have no idea how to animate each letter in a text this way.

Would be greatly appreciated if anybody could help me out.