It sounds to me like your situation would be as easy as upload with a PUT request (or PUT requests if you're chunking the file on the client side). And a GET request to your reverse proxy for downloading the file to the browser for display. Of course you could add compression on the server and client side here to speed things up.
.gltf files are explained pretty well on its wiki: en.wikipedia.org/wiki/GlTF
It sounds to me like your situation would be as easy as upload with a PUT request (or PUT requests if you're chunking the file on the client side). And a GET request to your reverse proxy for downloading the file to the browser for display. Of course you could add compression on the server and client side here to speed things up.
Draco compression might be something you want to look into: google.github.io/draco/.