From my little experience with nativescript, it seems to be a good framework, with strong support, but still have some improvement remaining.
I had some performance issues, with the UI, especially during http requests. However, I might lack of knowledge about this point; I know it is possible to set multi-threading but didn’t try, whereas it could help to reduce UI stuttering during requests.
About the data, no particular problems, Nativescript was handling correctly if you scale the data for a mobile use.
I was pleased to see that there are plugins for almost every functionality you would need !
In my case I used Gmaps (working as well on Android than on iOS), and Firebase Messaging.
I never used braintree, but there is also a plugin available.
Moreover, this framework is growing fast, getting updates and improvements regularly.
In conclusion, from my point of view I would say yes, Nativescript could fit your needs but it depends on your requirements level