Huawei HG8245W5 SSL handshake failure

This right there tells you what the issue is. The NodeJS server (and the ha proxy) do not have a cipher that overlaps with what the Huawei can do. So you will either need to add a bunch of old and insecure ciphers, upgrade the firmware on the CPE to support newer/better cipher suites, or trick the box to switching to http.

If the cpe gets an IP via DHCP you can try and see if DHCP option 43 is enabled in the CPE. DHCP option 43 allows you to send the ACS URL via DHCP.