In the art world as much as anywhere else, the pandemic and its attendant economic crises have done the most damage to those who rely on their labor, rather than capital, for their livelihood. Like other performing artists, Ei Arakawa felt the full brunt of the lockdown as social-distancing enforcement closed nearly all venues for his work. Approaching the financial details of his art practice with refreshing candor, the artist’s excellent recent show “Fees & Nerf” was as much an exercise in emotional and financial bookkeeping as a nimble pivot to potentially more pandemic-proof areas of practice.