Hey Sebastian,
I can't help you with the specific tool you're asking for, but I've done some basic PHP profiling on Moodle in the past.
To do this, you can use a built in feature in Moodle that is conveniently hidden unless the correct extensions are installed on your
server.
Documentation can be found here:
https://docs.moodle.org/dev/Profiling_PHP
In short, required packages are: "php-tideways" & "graphviz"
Afterwards, you'll find a new option "Profiling" under "Site administration" -> "Development", which will allow you to enable and configure the profiling feature.
On production, I'd suggest leaving automatic profiling disabled and going with on-demand profiling with POST-/GET-parameters:
You can then profile a page by simply adding "?PROFILEME"... or "&PROFILEME", in case it already has parameters attached.
This gives you an overview for a single call along these lines:
You can then click "View Full Callgraph" to get a graphical overview with some color coding on how much time was spent in which parts of the script:
