Debrid Media Manager (DMM) is a workbench for managing a debrid library by hand. StreamBridge puts the films you pick into Plex and plays them from there.
A free, open-source web app. It searches for torrents, shows what's already in your account, groups titles, removes duplicates, syncs Trakt watchlists and collections, offers a Stremio addon, and shares or mirrors libraries across Real-Debrid, AllDebrid and TorBox.
A Mac app that adds titles to Plex. You browse catalogs, pick a film or show, and it appears in your library for every Plex app to play. You don't sort releases first.
Collections in StreamBridge: films already in Plex, and lists you can follow to keep a collection current.

| Topic | StreamBridge | Debrid Media Manager |
|---|---|---|
| Its job | Puts the titles you pick into Plex | Decides what goes in the library: search, dedupe, group, sync, share |
| Where you play | Every Plex app | WebDAV, a media player, a media server or its Stremio addon |
| Release choice | Made for you | Yours: remux or encode, file size, provider |
| Cost | Free to use; Pro is a one-time purchase | Free and open source |
DMM is for people who care about the exact release: remux or an encode, the file size, which provider holds it. StreamBridge is for people who want the film to play without sorting releases first.
DMM decides what is in the library and leaves playback to whatever you connect. StreamBridge ends in your Plex library, so any device with Plex can play what you picked.
You want a full workbench for a debrid library.
You mainly want to pick films and watch them in Plex with as little library management as possible.