Python 3.10 is standard even in the latest debian version, nearly every Linux that you would setup today has python >=3.9 preinstalled. Unless you use some sort of "webspace" type of provider that only allows PHP, this should not be an issue (in fact I had a webspace once and it too had python, I just had to ask).

So python 3.10 is not an external dependency here, because external implies you need to install it.

But all the non-standard python modules used (humanize, ...) are definitly external dependencies and that can be an issue if you try to run your service in such a restricted environment.

Python is already included on most Linux systems