Alex from Branch.io here:
Deferred deep linking is tough to get right. I recently wrote an overview of all the things you need to consider in order to get it right. Short version: you're definitely wise to look at libraries for this instead of building it yourself.
Unfortunately, any system you choose for deferred deep linking is going to require a library in the app. This is by definition, because you need some way to process the 'deferred' part.
Facebook's SDK works only for Facebook, so that doesn't really help everywhere else. That leaves you with a choice between Firebase and Branch.io (there are a few other companies out there offering similar tools, but no one else has been in active development recently).
Firebase Dynamic Links also don't really work in every situation, so they aren't a full 'one system' solution like you want. And because Firebase is a modular system, implementing them still requires an additional library even if you're already using other Firebase features. If you want a more comprehensive comparison between Branch and Firebase, this is a good place to start. Firebase is a great system, and Branch works perfectly with it as a drop-in replacement for Dynamic Links.
The Branch SDK is extremely lightweight and is in many of the top apps you already use. We've taken great care to make sure everything is as performant as possible, so you won't be cluttering up your app with garbage code. It really is the closest thing out there to 'a single system' (yes, including Facebook!)
