Desktop bridge apps can request "full access" permission, which effectively evades sandboxing, but those apps are heavily scrutinized on review. In comparison, the Play Store has no manual approval process and an automated malware scanner that's industry-worst according to independent review. ;) Apple does a pretty good job though, and would be my general recommendation for mobile security.
Note that while Android and iOS both have numerous examples of malicious apps in their store, AFAIK, Windows Store does not (though there are definitely ad-ridden nightmares in there). I found their reviews annoyingly onerous for a literally 50-line UWP app with a single function when I tried to submit something.
The biggest benefit of their sandboxing though is not actually the security limitations of what they can access, but how it's installed, and more importantly, uninstalled. UWP apps are one-click remove, and do not leave any lingering garbage in the registry, as they have kind of like a "registry diff" inside their own folder.
Apps like iTunes which are notoriously messy for install and removal I prefer over UWP because it's much easier to purge them safely.
