Will just comment that I think there is huge value on having all pieces (front end/back end/apps) on the same language if at all possible, especially for small teams.
I've gone the other direction, which is basically "Typescript everywhere", or at least as much as possible, i.e. React on the front end, NodeJS on the backend, and Capacitor for apps (note Capacitor may not be appropriate for all types of apps but in our case it was).
I've gone the other direction, which is basically "Typescript everywhere", or at least as much as possible, i.e. React on the front end, NodeJS on the backend, and Capacitor for apps (note Capacitor may not be appropriate for all types of apps but in our case it was).