[2022] Can someone Help me pls?

Hello,
I have a problem with the game For Honor. I recently bought the game and now I want to play online with my friend. My friend plays on the PS4, but has linked his PS4 to Ubistoft connect. I play on the PC myself. I added him as a friend via Ubisoft Connect. However, I was surprised that he was displayed to me as a PC player. In the beginning we had the problem that he wasn't shown as online in the game, even though he was. After restarting the console, it was shown to me as online, but then we encountered a second problem. And he doesn't see me in his friends list in For Honor even though we're friends via Ubisoft Connect. However, he was also displayed to me as a PC player. Then I sent him an invite and unfortunately had to find out with him that he didn't see an invitation. We had also tried the mobile app where he was also presented with the invitations but as soon as he clicked on them they turned gray and said "Accept the invitation on Ubisoft Connect PC". But he doesn't have a PC and his Ubisoft Connect account is linked to the PS4. We both have crossplay on in the game and once managed to bump into each other in a random 1v1 battle so we should be able to play with each other if we made it against each other too. Unfortunately, since we have no experience with the For Honor multiplayer mode, I couldn't figure out why it shouldn't work.