As it stands, it's pretty simple
Having played Fortnite's Battle Royale mode since launch, I can attest to the handling of platform-related issues.
After sneakily showing the world that yes, Sony pouvez cross-platform play years ago, the console giant acquiesced and opened the doors for true cross-platform play. It was the first major case of each platform (mobile included) working together, but not everything is perfect (and may never be, due to the adversarial nature of console release).
There are a few known issues in terms of V-Bucks not appearing on specific platforms, apparently due to market and rights issues (likely out of Epic's hands); but recently an Xbox-centric issue surfaced regarding the new subscription service. Epic talks about this on its latest blog post for the game, explaining that the Xbox platform was having issues collecting its rewards, and that there were “early attempt” issues with unsubscribing.
As a result, Epic (in addition to answering help tickets and fixing issues) is giving away a free members-only emote. According to the blog, "Former, current, and new Fortnite Crew members will receive the emote upon login at any time from now until February 15, 2022."
Epic has been experimenting for a few months with a live version of its subscription service, "Fortnite Crew". The initial salvo involved the exclusive Galaxia skin, this month focusing on DC hero Green Arrow: both are the monthly rewards for subscribers. You'll also earn 1000 V-Bucks for the subscription, which essentially pays for your sub and keeps you in the Fortnite economy.
At first it seemed ridiculous - adding a subscription to a free game - but like most things Fortnite, it seems perfectly optional. I tried it for science last month, and it's incredibly simple and easy to use (or take out).
Fortnite [Epic] Crew