@yasinbs
1) Can you check for any browser console errors then share the errors here, if any?
2) Can you temporarily disable all other plugins and themes to check if the Web Stories saves when enabled by itself?
To find out more, I recommend you to troubleshoot your site using the Health Check & Troubleshooting plugin and enable its troubleshooting mode. This way you can simulate using your site with individual/all plugins disabled, to see if anything else could be interfering with the plugin. Note that this mode disables active plugins and switches to a default theme safely because it only affects the experience of the logged-in user.
Please enable the Web Stories plugin and let me know if the issue is present.