As I understand it it's the anti-cheat that is the problem.
If this is the only problem there is essentially only two possible ways to get Fortnite running in Linux:
Get Epic to support Linux
Crack the anti-cheat.
Since a major part of anti-cheat systems is preventing people circumventing it I would say that the easiest path would be getting epic to support Linux. One valid argument would be to play Fortnite on Steamdeck .
It is the anti-cheat. People have gotten the game to run via Proton, however you simply can't join lobbies no matter what be because of the anti-cheat. It would just be a matter of Epic enabling support for Linux/Proton in EAC on their side, however Epic has publicly been against doing so stating some pretty nonsensical reasons to why they choose not to enable support.
Looks like you can stream it from the Xbox service for free via edge, and you can install a flapak version of edge, if your distro can do flapaks
I just did a quick Google, I haven’t actually tried this so good luck! But it sounds like streaming it is the only way given the form of anti cheat used. Don’t think you can do it natively
Yuzu is an interesting idea, I haven't thought of that, but last I checked a few months ago, it was still not working, and I heard using wine to run the windows version can get you banned so I never tested it.
On my steam deck I've been using Xbox cloud gaming (free if you're willing to wait) or Amazon Luna (if you have prime), and they work decently well, much better than "not running at all".