Would you be buying them for mainly gaming though?
If so, I don't think they'd be a good choice. XM3/4 headphones don't support AptX LLC codec, which would be much better for gaming than the standard codec. I think unless you're playing games really casually and just for a bit of fun, the latency would be too much. A guy on Reddit confirmed the latency was too much when playing Rainbow Six Siege.
Best scenario for using XM3/4 for gaming, would be if buying them for music and occasional gaming use with wired connection.
If you're looking at wireless headphones specifically for gaming, Audeze Mobius would probably be the ideal choice. I think they are an extra £100 more than the XM3/4 though.