I actually really like the battle royal concept I just hate how lazy devs are which results in most of them being lame shooters. The my hero academia and VtM games could have been amazing.
Warzone will depend on how BF REDSEC does over the next few seasons and how far they go towards making it more like Warzone, because they don't seem to be interested in making it closer to the BF6 MP.
Beyond those 2, Apex Legends is still going strong and tends to survive wild player fluctuations. EA confirmed they are planning a major update to the game once BF6 release was firmly behind them, and "Apex 2.0" in the future.
Hero, BR, Extraction. Those are the popular FPS MP sub-genre right now. That + Counterstrike. They're different enough that they don't really step on each other's toes.
Apex blends 2(Hero, BR), and Marathon is trying to do the same(Hero, Extraction). But aside from that, there's not much cannibalism in the the genre at the moment.