We've just wrapped up the event, so if you'd like, you could do your arrival now as normal, and skip over the Hisui event entirely.

If you did want to back-date some things to the Hisui event, Kageyama would have received a Hisui exclusive starter at level 20 (basically, any non-evolved pokemon available in Hisui). His regular starter would've been waiting for him in Kanto/Johto, not gaining any levels.

But again, it's also possible to just forget all about that, and just intro now like normal.