Hello, Kevin,
The error shows because of the JS inline code added directly to your page. Could you please, give us an answer to who added this code https://prnt.sc/g9_fv04GVxKx ?
That code creates an issue for the swiper JS which is loaded from our theme.
We can recommend you few options below to check and find if any of those will fix the problem.
1/ Go to Theme Options → Speed Optimization → and activate => Disable Theme Swiper JS (option) ( https://prnt.sc/mgzMLXQnv7pp ).
If it does not help please, try the solution below
2/ Go to Dashboard → Elementor → Settings → Features → set Upgrade swiper library to ‘inactive’ => https://prnt.sc/BRHxas4RsaYr
If it does not help please, deactivate all 3rd-party plugins and check if the issue was fixed. If the problem was caused by any of the plugins, please contact with plugin’s author to fix the issue in their code globally.
Kind Regards,
8theme team