I am not very familiar with (label) printing solutions, but take a look at Zebra, which offers multi-platform custom print solutions: https://www.zebra.com/gb/en/products/software/barcode-printers/link-os/link-os-sdk.html
Mendix is a full-stack product that offers multi-device deployment. This is important because that also underpins the design philosophy. It is a full-stack product first, meaning it has a server and a client component that are tightly integrated.
The server component is a runtime that interprets a model. This runtime can be extended with Java code, allowing you to do new and exciting things in your model.
Since it is possible to access native code from React, a widget could technically call native code like a print driver, but this would need to be native code that iOS can run so you would need to port your driver to Swift. From there you can then include it in your application bundle and access it in your Mendix Pluggable Widget written in React.
I would personally not take this route with Mendix, it would make a lot more sense to have the server runtime do the printing as that would move all the difficult bits to a platform over which you have more control. I do appreciate that this might not be an option as you might need local connectivity due to unreliable internet or security.
TL;DR Mendix would not offer any advantage over Swift when it comes to the printer driver as you still have to implement the printer driver. Mendix does offer advantages for the rest of your app and takes care of a lot of the complexities of integrating your iOS app with a back-end system, assuming you will use the Mendix server runtime.