XAMPP is not designed for production use, I highly recommend you read this thread: https://community.apachefriends.org/f/viewtopic.php?p=192464 and other threads relating to this. You mentioned your deployment would be on a local network however if the web application will handle company secrets or sensitive information you should not use XAMPP unless every user is trustworthy. If you do use XAMPP, the company should know in advance they will need to port to a production ready web server to expose any part of the system online. If you are limited to Windows hardware you could use WSL2 to install Ubuntu (or other Linux distros) on a Windows system. https://docs.microsoft.com/en-us/windows/wsl/install
As already mentioned, XAMPP is not a package to be used for production. So setting up NGINX woudl be fast answer given the choices you look at. As usual, things are not just black and white, so you could also use the standalone components of XAMPP that you need.
My first check would be what do I need? In your case I assume a web server, a scripting language (I assume you mainly want to use php, not the also integrated perl in XAMPP) and a SQL database
For the Webserver you can use Apache or Nginx - both run on Windows as well as Linux, and both can run scripting languages. And if you are new to set them up I would say they can have an equal learning curve. For the scripting language it is the choice of what you are experienced with, but I recommend to only install the needed one(s) - as each adds onto the maintenance and hardening efforts. And for the database you can install MariaDB on its own.
The big plus of going through the effort to set them up manually:
you can patch them independently in case any security issues come up (take them seriously and apply patches timely!)
you can decide to run web server + scripting engine on one and the database on another machine
Once you know what you need you should then check with the one who maintains the server afterwards (not sure if that is you or an admin in the company you write the application for). Based on that evaluate what of the blow sounds best for (both of) you:
For all above tools I would recommend running them on Linux / WSL2 (WSL = Windows Subsystem for Linux) - as waiting for Windows binaries can sometimes take longer then the Linux ones. And even "just" an intranet application should be taken seriously regarding security. Rouge employees are nothing to underestimate.
It may also be worth looking into the use of containers (e.g. https://hub.docker.com/r/webdevops/php-apache & https://hub.docker.com/_/mariadb), but these should run in the WSL2 (if Windows is needed) or on Linux for best performance. It adds learning about docker and how to connect the two containers (so that they can talk to each other) but also allows you to more easily migrate to other hardware if needed - and takes away some needed setup (e.g. the integration between Apache and php).
Sorry that this answer is a bit longer, but I want to help you find something that works in the long run for you and the company you code for.