How to fix Elementor stuck on the loading screen We can't support third-party plugins but you can follow the official help guide of Elementor for this case: https://elementor.com/help/elementor-not-loading/
How to update the theme? Just install the new version as regular theme (without demo installation). Feel free to ask for support if it’s not clear!
Does the theme support custom fonts? Can I use my own font? Yes, you can choose any in Elementor Global settings to set globally or change only on a specific demo.