I've imported a PowerPoint into Captivate 2019. Some of the slides have anmation, but the animation is moving too fast. Is there a way for me to time the animation to match my voiceover?
No. PPT slides are imported like a sort of movie slides. You have little or no control over anything. That is one of the reasons I never recommend using PPT as start for an eLearning project. Use it as a Storyboard, unzip the PPT file which is a zipped folder (as is cptx) and extract the assets that are useful. Import those assets to the Project Library of a new project with the wanted theme and create from scratch. That way you'll have full control over everything.