That's a weird question, you are comparing a desktop OS with a phone OS (except you are talking about Windows phones, but I don't think you are?).
All it takes to kill your Windows installation is double clicking a random .exe file (and being unlucky that Windows doesn't warn you about this particular file). And nope, if it is a custom program your antivirus won't detect it either. Every time I hear of a company getting a crypto locker on their systems it was over a Windows PC (mostly by email). I haven't heard of your average company getting compromised by a phone yet (but those phones usually don't have network access to shared drives..).
Android is relatively locked down, a lot more than Windows. Even if someone sends you malware per email, there is no easy way to execute it on your phone. It's also not true that you can just install a rogue APK in two clicks, you have to do the following steps:
- Open the Settings app on your Android device.
- In the Settings menu, tap Apps.
- Tap Special app access (or Advanced > Special app access).
- Tap Install unknown apps.
- Select an app to use to install an APK file—your browser and file management apps are the best option here.
- Tap the Allow from this source slider to allow APK files to be installed via that app.
Definitely not something that happens by accident :)
Overall for your average user I'd say Android is safer.
Oh and I didn't answer your original question: If you have to select between Ruby and JavaScript, 100% go with the JavaScript course :)
Though DevOps and "free" or "open source" doesn't really mix. The moment you touch DevOps you'll either land at Amazon (AWS) or Azure (Microsoft) or Google (Google Cloud).
Sure, in theory you could set up your own servers with your own clusters, but then you're a system administrator and not DevOps.
Btw. Azure might be Microsoft, but they have plenty of Linux options on there, it's not a Windows shop at all.