Now, setting up a bunch of bridges is indeed harder, but they are deliberately entirely separate apps, each with their own foibles. But just like you wouldn’t blame Apache httpd for some fiddly 3rd party Apache module, I wouldn’t blame Synapse for the complexities of running bridges.
But again, I appreciate you putting that into perspective. Synapse by itself really isn't too bad. But for it to be actually useful for myself takes a lot of work.
what about whatsapp for example? do i have to have an existing whatsapp account which constantly remains online and interacts on behalf of my matrix?
The general workflow is after you install bridges that you configure your bridge to your existing account on the other platform. So for Signal, you open a chat with the Signal Bridge bot and issue a command to link to your account and then it walks through that process. Once the bridge is configured with your external account any new DMs and group chats from those external accounts will show up as DMs in Matrix.
Hopefully that makes sense! :)
After my comment, I decided to give Matrix a try again and setup a fresh Arch Linux VPS for it. I didn't run into any snags but it took quite some time to get everything configured. It probably took me a solid 2 hours just to get everything up and running (Synapse + bridges for iMessage, Signal, Discord and IRC).
Not many applications I self host require as much setup as Synapse!