Hello, thank you for your answer :-)
Yes it is RJ45.
The problem is that I'm always afraid that Unraid doesn't recognize the hardware.
I noticed that my small ITX motherboard doesn't allow adding a new network card, so I'm thinking of changing the motherboard and buying one with an integrated 10 GbE RJ45 network card.
I found this motherboard, ASRock W480 Creator.
It is quite expensive but it is one of the cheapest with 10 GbE integrated...