I think Paul the answer is no. Fuji RAW support seems to be very patchy with photo apps, don't know why. DXO for example can't open any of the Fuji RAW files I have, not a single one.
The upshot is that it will open, but the data will probably not be interpreted correctly. RAW Therapee does, apparently, support the XT30, but that could be apocryphal.
So it could be that Affinity Photo is not for you. That said, I don't usually open RAW files with it, I use 'send to' from ON1 which exports PSDs, and edit those. I do find Affinity much easier and quicker to use than Photoshop, but it's that old horses for courses thing again.