I haven’t a test installation with 500+ Static Pages (assume you mean Static Pages) to test that many ticked options.
My instincts would be to avoid using so many options for a widget, that’s a lot of saved options and might be taxing MYSQL (I’m making an educated guess as can’t easily test it).
When you say “stuck whole web” does that mean you have a white screen when loading the website (500 error) and you can’t get into your Dashboard?
If so means your site probably crashed, could be due to the number of options having to be read. Might be MYSQL went down (crashed), might need a reboot.
If you can’t get access to the site due to a plugin the first thing to do is delete the plugin from your server via FTP or similar: only do this if you can’t log into your Dashboard. I wrote a tutorial for deleting another plugin at https://stallion-theme.co.uk/how-to-manually-delete-a-wordpress-plugin-using-ftp/
For the Display Widgets SEO Plugin use the instructions above, but where it says
/wp-content/plugins/ewww-image-optimizer/
substitute
/wp-content/plugins/display-widgets-seo-plus/
When the plugins files are deleted WordPress deactivates the plugin. If your sites server is still up and running (nothing crashed) it should work normally minus the plugin. If something crashed, whatever crashed would need a restart/reboot.
How many Static Pages does the site have?
If it’s thousands I don’t think you’ll be able to use Display Widgets SEO Plus to manage widgets with so many ticked options related to Static Pages. I wouldn’t be surprised to see your Widgets page (under “Appearance” > “Widgets”) timing out while trying to open/save the “Static Pages +/-” options on each widget.
David
