According benchmark at https://github.com/php-service-bus/performance-comparison between pure php, symfony/messenger, golang and php-service-bus/service-bus; symfony/messenger is far worst. I don't really have suggestions how to improve it, but I think this issue should be here as placeholder for anybody willing to take a look. Please excuse me if such topic already exists somewhere here.

Pure php (Time spent: ~ 4m20s)
symfony/messenger (Time spent: ~ 7m25s)
php-service-bus/service-bus (Time spent: ~ 1m)
Golang (Time spent: ~ 0m 22s)