Laravel Valet php-fpm already listening on valet sock
After days of screwing around I found an answer on serverfault that suggested deleting the listening sock. So I ran rm ~/.config/valet/valet.sock
and immediately the tailed php log showed
[08-Sep-2019 16:55:48] NOTICE: fpm is running, pid 10316
[08-Sep-2019 16:55:48] NOTICE: ready to handle connections
So I guess that's all there was to it!
Run valet install
that should solve your problem. After upgrading Valet version it is required to run this script.