Mobile operating systems have really good security models, and native apps are even more isolated compared to the websites.
I really wish that we would have similar isolation options on desktop/laptop OSes.
I'm afraid it's the other way around. Browsers are (generally) better at sandboxing than OSs. Browsers are paranoid by default. They have to be, because visiting a website is just a click away (compared to multiple clicks/taps to install a native app).
For example, Chromium was able to mitigate Meltdown/Spectre within days, even if the OS was still vulnerable. (Chrome already had site isolation ready to ship, a feature that completely isolates websites into their own process). Even better, Chromium browsers tend to update themselves (or via Google Play) automatically.
Meanwhile, OS vendors were scrambling to ship an OS update.
(Also, worth mentioning that iOS users were vulnerable until Apple shipped an OS update, because every browser on iOS has to use Apple's WebKit)
But it's still a lot better than apps, which give the developer more control without (in most cases) any tangible UX benefit. Just as an example, Reddit doesn't need to have an app, all they do is display text and images, along with some interaction, and they especially don't need to lock some content behind the app (I recently got a popup when trying to view a post saying that "unreviewed content" is only available in the app, despite the post clearly loading for a split second before the popup).
On top of that, platforms like Reddit and Facebook tend to prefer native apps because it's easier to keep you within the app. Even if you click a link to an external website, for example, Facebook will open that link in an in-app browser (unless you find the opt-out). A few years ago, a researcher found out that these apps often inject their own javascript into that in-app browser. In theory, that means FB can track you even on external sites, even if you do not accept cookies for that website. You just brought your own tracker. Facebook then decided they should ship their own entire browser engine, giving them even more control.
https://webventures.rejh.nl/blog/2022/in-app-browsers-are-tr...