The character played by Rory Culkin is the young Joel Schumacher, later to become veteran Hollywood director of St. Elmo's Fire (1985), Batman & Robin (1997) and Falling Down (1993). Schumacher started out in the industry as a costume designer working on such Woody Allen movies as Sleeper (1973) and Interiors (1978).
This was originally intended to be an 8 part series, but COVID happened in the middle of production, by the time production started up again 6 months later, the series was rewritten and re-edited down to a 5 part series.
Joel Schumacher actually directed Rory Culkin in Twelve (2010) - the actor playing him in this episode.