I’d argue that Signal is the cleanest and simplest messaging platform out there
If anything, the complicated thing might be that the data is stored locally on your device, so you need to take extra steps to back up the data
But every platform has some small quirks to learn. People figure out how to adjust to all the other “big” platforms because they want to use them. It’s not that Signal or Fediverse is harder, some people will use it as an excuse to feel justified in not switching