hi, actually the ethernet cable is connected on the LAN1 port for the NAS side, ILO ethernet cable is connected on the dedicated ethernet port.
My NAS with ILO cable disconnected is fully reachable from internet from 2 different DDNS (1 updated from NAS and 1 updated from Home Assistant server)and from my fixed IP.
On my DSM there are 2 different SSL certificates, one automatically created by DSM (with expire date 12/02/2023) and onther one create by me with let's encrypt (with both my ddns profile, expire date of this one is 28/05/22), the default SSL certificate in use for all service is the last one (FTPS, synology drive service, etc.).
With ILO cable connected I can reach from Internet my DSM machine from PC browser but not from all apps (when I try to connect and I receive error message due to SSL certficate, if I go on SSL certficate details I read the data of the ILO SSL certificate).
I saw on your config data that you also use an HP microserver 8 for DSM, wich is your situation, you have my same problem?