It is not really a proper language. It is designed to run to generate HTML dynamically but uses outside of that are pushing it. It is also problematic that Nextcloud mixes code and data. It is also slower than compiled languages like C, Go or Rust.
I think Go is really good for web applications with lots of server back end code since it is fast and static while being memory safe and easy to read. The Go syntax is cleaner than PHP and less hard to maintain.
How did you get the certs? Was it though a DNS challenge or web server on port 80?