In the auditorium scene, the crew really struggled to figure out the eye lines for Geena and Rigby. To solve this, they studied a scene from Cherry (2021) where two characters look at each other in an audience. It worked.
Geena's bedroom was a set built in two hours inside a university common room. A TV is hidden behind the yellow tapestry on the wall and the bed was supported by several apple boxes since the editor sat on it and broke it the day before shooting began.
During the auditorium scene, a CD for Emma Ryans' album can be briefly seen resting on the sound system. This features full designs for both the front and back (including a full track list and some small Easter eggs that are never visible in the film). The album is titled "Broken Mirrors", completely unrelated to the windy mishap that broke Geena's bedroom mirror days later,