Question: remote servers and port forwardinh

I have servers that are dhcp assigned and only expose port 80 and 443. The WAN is also dynamic ip.
Think of IOT devices.
I can't change this or touch the router.

As far as I can see rtop Bot will not be able to reach the embedded servers.

Any ideas ?
I could put an agent on each embedded server to call out and do NAT punch through on port 80, but that it
