#1. Please don’t add slider widget in header, it will show this slider on all pages.

#2. You install a lot of different plugins, which can lead to conflicts with themes and other plugins. Please double check and remove all unnecessary plugins.

#3. Widgets lost may be due to cache (I see you installed 2 cache plugins, this is not necessary), due to different active theme…
I have re-added the slider widget to the home page for you, please double check all the notes above