Issues in configuring external smart proxy

Hi all guys and first of all thanks for the support as usual,
we are trying to configure an external DHCP smart proxy ( 3.11.0, IP:193.205.32.8) for our Foreman 3.11.0 server (OS Ubuntu 22.04.3, IP: 10.10.0.7). We currently use the internal Foreman smart proxy server as a DHCP, TFTP, PXE system service on our private subnet and we are configuring the external one on a public subnet. The external proxy works fine as DHCP, but it seems that the configuration as tftp and pxe proxy doesn’t. I’m not sure whether the external proxy can also manage the tftp and pxe service or these functions have to be managed by the main foreman server.
Currently the configuration for the tftp is:

47. Set tftp_listen_on, current value: "both"
48. Set tftp_managed, current value: true
49. Set tftp_manage_wget, current value: true
50. Set tftp_root, current value: "/srv/tftp"
51. Set tftp_dirs, current value: UNDEF
52. Set tftp_servername, current value: "193.205.32.8"
53. Set tftp_replace_grub2_cfg, current value: false`

Any hint about best practice and procedures for configuring an external smart proxy is very welcome....What we are trying to do is to perform the provision of a server (vm or bm) on this public subnet, just the way we do it on the private one using the main foreman server with the internal smart proxy.
If you need more information I'll try to provide them...thanks a lot.

Giorgia