Update:
I vacuumed the fan and replaced a piece of tape that had lost its grip. Started startup repair. It ran surprisingly long. Then came a message saying it couldn't repair automatically. I clicked whatever confirmation button there was and it shut...
I vacuumed the fan and replaced a piece of tape that had lost its grip. Started startup repair. It ran surprisingly long. Then came a message saying it couldn't repair automatically. I clicked whatever confirmation button there was and it shut...