I've been hoping (without good reason apparently) that Google Fi accounts would be harder to social engineer and SIM swap. Since we all know it's impossible to

I've been hoping (without good reason apparently) that Google Fi accounts would be harder to social engineer and SIM swap. Since we all know it's impossible to get a human at Google to talk to you, I figured an attacker would have to take over my Google account in order to compromise my phone number instead of the other way around. Is there any info on how the attacker managed to do the SIM swap against the Google Fi victim?