By all accounts the cast and crew were very up to it (the cast had to lobby the studio to let him direct, because he was essentially blacklisted at the time from directing), but Welles was probably the most talented director in the world at that point yeah. The Citizen Kane of directors, some would say lol

His previous few movies were actually the opposite: because of extreme budget and production constraints, they were shot over a period of years in bits and pieces and had to be cobbled together later. Orson was already very used to making films with extreme limitations