How to use WebRTC as a tunnel to receive large files on a site with limited resources?

Question

PHP

There is a PHP server, I would like to place large files there, but the server resources do not allow it.
There was an attempt to raise your local server and open access from outside, but the computer is behind symmetrical NAT and there is no access to the router. (VPN is somehow blocked, OpenVpn does not work on ports 43 and 80, but it works on 25000 and even that is weak)
WebRTC works, so I would like to refer to large files that are on the computer from the PHP site via WebRTC.
Idea:
My computer (local server) is online all the time.
Someone visits the site, selects a file. After that, a connection is established with my computer via WebRTC, access to a file is opened.
Can this be implemented somehow?
Maybe use something else instead of WebRTC?