welcome back. i don't know much about the Ionic etc., but if you were into Meteor you likely have a great handle on JS, so you might consider React/React-Native.
React is more or less a front-end framework that jives nicely with firebase, and React Native takes the React way of building apps & puts it to work on cross-platform mobile apps. You write most of the app in Javascript, but the results are apparently more performant than many of the 'write once/deploy everywhere' solutions (see:
https://www.youtube.com/watch?v=juWhxCz1Wmg)
Firebase works exceptionally well with React, imo, as (using 3rd party libraries) you can effectively connect your presentational UI elements directly to your Firebase data & letting things just sort of take care of themselves. Redux is a helpful library here, but does add a layer of complexity.
If you do go that route, there are a number of boilerplates available, but typically the projects involve Webpack, Babel, and a few other useful tools (grunt, gulp, etc., seem to be losing market share in the React community).
(disclaimer: i'm a relatively new developer and have only really worked w/ React)