Hello, Pavlin Grutsov,
Thank you for your response.
By checking your real website (not staging) we found you have only 2 widgets added to the Shop sidebar → https://prnt.sc/RcxyriXMVpnX
Once we added filter by attributes widget → https://prnt.sc/ANbHmmEUczNd it shows on frontend → https://prnt.sc/LiMMrl-I0V60
We think the reason for not showing some widgets could be in case you add many widgets and each of them contains many options as this one → https://gyazo.com/b86db60dab3a00fd4a4419967af0c362
The loading time and amount of widgets (with its options) are depended on WordPress memory size and server response time. We would recommend you minimize options for widgets or contact your hosting provider to make the best parameters for your website to load fast and correctly.
Kind Regards,
8theme team