How to speak to a client about Carousel or sliders in website banners and their usability

Currently, I am working on a university website redesign project. The complication is that they used a lot of image carousels or sliders on their existing website. For example, in the banner, 10 events/programs images are running inside the carousel and some have a hyperlink to a dedicated page.

I am planning to remove the carousel with a hero image and move the other image to events and programs gallery since too many messages will miss the important thing. And the chances of conversion are below 1%. How could I convince the client diplomatically? Because they are crazy to see carousels to show different department images in the home page banner even after I tried to convince them that they are conversion killers.