Animate text in final cut pro: knocking previous text further from centre
The Apple tool for that job is Motion and it can make plug in for iMovie or just do the work you want. Adobe Premiere Pro probably does what you want, but instead of a one time $50 charge - that is $20 a month subscription. You do get a free trial of Premiere so you could make sure it would work for your project.

You could possibly find someone who already knows motion to make you a plug in or find one that works for your needs, but the general solution to making custom text animations is to use Motion or the Adobe CC suite tools for video 


https://filmora.wondershare.com/imovie/top-5-imovie-plugins.html