unable to accès to a specific port with double nat configuration

[Maestrie]

Hello everyone,

first of all, sorry if my englis is bad, i'm french and do not practice very often English.

so I have a problem with my system set.
to explain a bit the situation :

my equipment:
1 box/router from my ISP
1 OPNSense server (for the server network)
1 Wifi router (for mu local private network only for users)
1 proxmox server (with various servers on it but thats not important for now).

(see my set drawing in the attachement)
the red arrow means i'm not able to go through,
the green means that it works

I'm at home, with a general public ISP box. the router is configured with dmz redirected to the OPNSense server.
behind my OPNsense server, i have a proxmox machine with varius ports needing redirection (ie : 8006 wich is the webui port)

i folowed some tutorials such as this one:
https://homenetworkguy.com/how-to/use-opnsense-router-behind-another-router/
excpeted to allow dialog between two machines exixting in the ISP private network.

I manage to do the first part, but i was unable to get access from the outside network (my ISP public IP) i keep having authorized trafic, but i'm allways getting a "ERR_CONNECTION_ABORTED",

I suppose this is just an idiot thing to do and correct the problem, but i don't seem to be able to put my finger on it... is it possible for someone to help me?

thans for your time, and remember, i'm no network technician, so if i forgot something, please ask.

thanks for reading me anyway

Maestrie