Since your cms is running on kubernetes, you could have a lot of the work of instrumenting your application cut out for you if you went with the Opentelemetry Operator path, it would inject a bunch of defaults for you for you.
https://opentelemetry.io/docs/kubernetes/operator/automatic/
But I'm seeing now that there's no PHP option on there. I'm still keeping this here just as something you should keep in mind because it simplifies this process on other languages.
You can still get instrumentation applied on PHP, but you might have to get a more hands-on and implement some hooks within the code. You should start reading from here:
https://opentelemetry.io/docs/languages/php/automatic/
If it's only (existing?) logs you want, you also have an alternate path, which is to ensure all your logs obey a specific format (or enrich them upon collection yourself) and have something like a fluentbit or otelcollector (filelogreceiver) tailing the logfile or the stdout of your container and exporting to signoz.