Website speed is really slow on mobile.

We have some general recommendations for you at https://www.ads-software.com/support/article/search-engine-optimization/

Particularly about mobile compatibility, you may also want to discuss the issue at your theme’s support.

The site is showing 56 console errors along the lines of:

Access to font at ‘https://xxxxx.b-cdn.net/wp-content/plugins/ovic-addon-toolkit/includes/options/assets/lib/font-awesome/webfonts/fa-brands-400.woff’ from origin ‘https://xxxxx.pl’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

You should try and fix these first.

You could also try installing a plugin like https://www.ads-software.com/plugins/webp-converter-for-media/ that serves more efficient WebP images.

I have found that replacing a slider with a fixed image has a significant improvement on mobile page load, since even if the slider is hidden on mobile view the stylesheets are still loaded. There are lots of discussion on whether sliders are worth the impact on page load. Perhaps create a test page with a fixed image and see what the difference in mobile load time is.

There may be limits to how much mobile speed gain you can achieve when using an all-in-one theme like Elementor, but this plugin may also help: https://www.ads-software.com/plugins/autoptimize/

Good luck!