Since Hyper-X v4.0 you can upload custom font on your website. Just navigate to Appearance > Custom Fonts page. In the first field enter Font Name (font-family), this is very important, because if this value is incorect your custom font will not work. After that, upload all accepted font files you have. If you did everything correctly you should see your new font in any Font Family select of the Theme Customizer.
This is how it will look like in the Theme Customizer.
Please Note: You should enter Font Family and NOT font file name (3265E8_0_0.ttf) like on the picture above.