Why is the stars CSS broken? And why do it slowed down my site loading speed?

1. Please see my site, the 3rd last section: https://buytechgadgets.shop/ the stars look broken and doubled in the background, which is giving too much fake feeling.
2. When I’m deactivating this plugin, my site’s loading speed gets 2 to 3 seconds, and on activation, my site gets slow enough to more than 20s loading speed.
Why is this happening? And Can you please solve this?