The message
413 Request Entity Too Large
means that your server does not allow files of this size to be uploaded. To be more precise, it is a security restriction on the nginx web server. Your host, who is responsible for these settings, blames WordPress for the reason, which is not true.
Whether you can upload the file completely via cPanel depends on whether this restriction also applies there or not. You should check the success via FTP and I would recommend paying close attention to the file size there. If you want to synchronize an incompletely uploaded file in WordPress via the above-mentioned plugin, it could fail because WordPress does not recognize it as a media file due to its incompleteness. Then this method would not work either.
In my opinion, you have 3 options:
a) Upload the file via FTP (not in cPanel). There should be no restriction here, unless your host has set one up.
b) Ask support to adjust the maximum size mentioned above in nginx. However, for security reasons alone, they are unlikely to agree to this.
c) Upload the file somewhere else. If it is a video, there are many platforms suitable for this, starting with YouTube.
And a general tip (especially for point c))): a file this large must also be accessed by a visitor to your website. Each individual access then causes 1.3 GB of traffic. So check how much traffic your contract with your hoster actually allows. If you reach the limits here, your hoster could also throttle the speed of your hosting or block you completely. Hosting videos somewhere else is therefore definitely preferable.