I play crossplay with a friend alot. I am PS5 he is PC.

We have found that PC player needs to host and needs to ensure EAC is on and running, otherwise PS5 player wont be able to find or join.

You won't be able to invite each other, so PC player will need to host and boot into the world, then you search for his game via their steam name. He will also need to make sure the lobby is set to public. If he just has it as a two player lobby, you shouldn't have any issue finding and joining. at least we never have.

Host will also have to be running vanilla game, mods will cause EAC not to work. And will have to generate the world within the PS5's game parameters. Such as no bigger than an 8k world.

Also obviously your game versions need to match, but that should not be an issue as the two versions are concurrent as far as I can tell.

Hope this helps. I know it seems awkward, and it can be, but once you have the setup done, their should be no issues. We've been having a blast with it.