So honest question as I am now looking into matrix as a solution to combine multiple messaging channels. Does it play well with signal/telegram these days or do I need to constantly update various connectors and hope for the best?
I have been self hosting a matrix setup for a few years now, using the spantaleev ansible playbook. It does require updates roughly once a year to keep up with changes of the 3rd party chat APIs. Generally that involves logging into the server and running 'just update' followed by 'just install-all', but occasionally there are changes that need updates to the playbook as described in the release notes. In the worst case, if one of your bridges does go down you can always fall back to the vendor client for that protocol until you get the bridge updated.
Overall it has been absolutely rock solid, and the new element x app has been night and day compared to the old one.
Feels a lot like the days of using Pidgin chat, but since the bridges run on the server you only need to authenticate once instead of going through the process for every device.
I've been hosting Matrix Synapse and mautrix-WhatsApp bridge for many years. Due to WhatsApp changes, bridge has to be updated periodically (about 1-2 times a year IIRC), but it has worked pretty reliably otherwise.
You do have to keep bridges up to date, because they need to remain compatible with the internal APIs of other platforms. Beeper.com (mentioned by a sibling comment) is a commercial deployment of the mautrix matrix bridges, along with some propietary components. You can deploy the exact same bridges using their documentation: https://docs.mau.fi/bridges/ - although you won't have access to the propietary beeper client or hungryserv.
Your best bet for that is almost certainly beeper.com, which isn't FOSS, but specialises in combining messaging channels and is built on Matrix. Otherwise, you do have to run your own bridges and hope for the best, and moreover the bridges re-encrypt Signal and so miss the point of its end-to-end encryption. On the Element side, we're not focusing on bridging currently.
