A bit ironic that you compare it to microservices, because that exact property of PHP makes it massively unsuitable for microservices and scaling, because it requires another layer in between the microservice platform handling the scaling, and the actual application.
PHP has it's uses, but I wouldn't go beyond a classic monolith or "backend/frontend" style application with it, with very little, manual scaling. If you go beyond that, you could probably manage to do that with a proper architecture and doing wonky stuff, but would it be a good fit? Absolutely not.