If you want all the CSS properties, use a PWA platform like Ionic. Web development !== Native development. All those CSS properties you want have to be linked to underlying native properties to handle their styling equivalents.
This is far from easy, especially when working with complex view types. Anything stylistically you want to accomplish can be through NativeScript by either a 3rd party plugin (i.e. there is a drop shadow plugin) or accessing the native API layer.
NativeScript’s mantra is not “we are just like React Native” or “build native apps using web css”. It is:
Build amazing iOS and Android apps with technology you already know
When you try to encompass too much with a framework, you lead to performance hits, knowledge gaps or worse: failure. The NativeScript team has been very deliberate about the properties they support and are always welcoming to a PR to introduce new ones. When you are using these properties, it needs to be crystal clear of the underlying native CPU required to accomplish it.
I don’t think you understand what NativeScript is, which is why you are expecting all these “web things” to work with it.
Alternatively, pass all your raw HTML and CSS into an WebView. It’ll render just like a PWA will, but is less extendable and modular in nature.