if I can get it working

It’s really as simple as starting one container per chat service, with a config like this:

services:
    beeper-<service>:
        image: ghcr.io/beeper/bridge-manager
        restart: unless-stopped
        environment:
            - MATRIX_ACCESS_TOKEN=<your beeper matrix token>
            - BRIDGE_NAME=sh-<service>
        volumes:
            - ./beeper-<service>:/data

then messaging the @sh-<service>bot:beeper.local bot user, and logging in to your chat account.

I’m using the Beeper Matrix server, but self-host their bridges. That way the de- and reencryption is done on my server, and Beeper only sees encrypted Matrix messages. It’s extremely easy to set up if you’ve used docker before, much less work than running a full Matrix server yourself.