Hi Ellen,
I hope you are well today and thank you for your question.
I visited your site and found the slider is running with normal speed as the slider displayed on this theme demo page https://colorlib.com/dazzling/
If you want to change the slider speed then you can so so by referring the solutions provided in the following topics.
https://colorlibsupport.com/t/slider-speed/#post-14314
https://colorlibsupport.com/t/slider-timer/#post-42590
Best Regards,
Movin