Windows

Your question boils down to a decision between two programming languages, and it's hard to give advice for you. It heavily depends if you already build up a huge skillset in one of the mentioned languages.

The Qt framework is known for its nice and structured code, documentation, and available examples. Also, if you think about performance Qt and modern C++ (11,14,17) is your friend. As you referenced "great design and looks pretty nice" you should definitely have a look at Qt's own solution to address fluid and modern user interfaces for mobile and desktop devices: QML.

Javafx is actually quite good, and feels modern. Some widgets are quite hard to master though (for example the table view...).

I have written a low-code development framework ( Open Lowcode ) based on Javafx. You may want to have a look if it can help you. It is purely open source.

If you just want the basic orchestration between a set of defined hosts, go with Docker Swarm. If you want more advanced orchestration + flexibility in terms of resource management and load balancing go with Kubernetes. In both cases, you can make it even more complex while making the whole architecture more understandable and replicable by using Terraform.

I don't know much about Xamarin but I know about PyQt and React Native.

However, I don't recommend PyQt because the apps made using PyQt are not that suitable for mobile apps. If you take a look at the PyQt interface, you will be able to see that the features are more of a desktop apps kind.

React Native uses JavaScript. React Native is immensely flexible in upgrading your apps because it allows you to formulate your app code into independent blocks.

In Xamarin, you have to write the code in .NET . The best thing about Xamarin is, that it extends the.NET developer platform with tools and libraries specifically for building apps for Android, iOS, tvOS, watchOS, macOS, and Windows

While the best choice for you depends on various factors but React Native app development is a promising overall choice. In today’s scenario, React Native has steady growth, flawless code structure, and brilliant and large community support. We suggest you go for React Native for your next project owing to its outstanding support from developers, easy availability, and cost-effectiveness.

It seems like your app is not really using any native functionality on the phone. I have experience with cross platform iOS & Android development. They are all really good tools! Xamarin (all the project on the website portfolio I attached) is awesome for accessing native functionality (NFC, Sensors, Bluetooth, etc), and I have built apps that have millions of downloads, some that hit Top 5 on Utilities, another that hit Top 50 in Finances. You just have to look at what your application intent is, it seems like it's just to read and post data. For that they are all pretty good, but you should also look into Ionic which may serve the same purpose

Take Unity for development as it is a full engine, with better tools to develop UI, use 3D assets, develop the integration with the API endpoints and deployment not only for Web (w/ WebAssembly) and Desktop, but also Mobile platforms (Android and iOS)

Well, it is alway a matter of taste.

But to share my own experience, using Unix Shells ever since 1988, and also PowerShell for some period of time. If you want to script Windows OS as an Administrator, PowerShell is a good option. If you want to administer all different kinds of UNIX OS, bash will be available on almost all of them. If you want to develop software and have the freedom to choose, I recommend zsh, better yet oh-my-zsh.

I would go with Python, it is fast to code, readable and very powerful without giving you too much to think about (e.g. memory management). If you're looking for speed, Cython is a fairly good way to get there, since Python is a C-based language it can be compiled to C using Cython and will get you a very significant boost in speed! You can also make use of C libraries if you prefer. The only downside to Cython over Python is that it is compiled and not interpreted, which can make debugging a pain (but you might find yourself doing most of the debugging in Python before switching to Cython). C languages are a bit of a pain to read up on (API, libraries etc.), but Stack Overflow has you covered in most cases!

Python can be linked with C++ both language are similar in many places (using same libraries or concepts to build libraries) - except memory and static types. C++ is more assembler and have different syntax (need 3x-4x coding more).

If you do engineering it is perfect stack - Java is to slow in coding (4x more code) and little faster than Python - whatever it is hard to mix Java/C++ what is easy Python/C++.

In the most program you do not need super performance but if you need C++ is the best and have rich Object Language much richer than Java and more poor than Python. Python is true object language - everything is object.

Whatever sometimes more important is framework than language for specific use.

Buddy ,you should go with RObot framework as per my experience,let me be clear i dont have any experience in playwright. We have similar kind of situation that time we used robot framework for native Web ,api and Android app . RF gives you privileg to automate any kind of application . Rf is open source , timely library upgrade like selenium 4 webdriver manager ,sikuli . And it is easy to maintain easy to learn