Fortnite actually does allow cross-platform play, meaning you can play with friends on different devices like PC, console, and mobile (except for iOS and Android due to platform restrictions). So, it’s likely not a general limitation you’re facing.
To understand the issue better, I need some more information:
Once I have this information, I can help you troubleshoot the issue and figure out why you’re not able to play cross-platform in Fortnite.
Here are some resources that might be helpful in the meantime:
I look forward to helping you get back to playing Fortnite with your friends!