Fediverse doesn't actually solve a problem I have. I'm not on xitter or instabook or myspace and don't want to be. The one saas i really need is email, which is 1. Already decentralized and 2. Getting harder to self host every year due to the escalating war between slopspammers and security measures.
Signal solves the async messaging and phone surveillance satisfactorily for my "threat model".
I host my own mail, I really did not have any issues for around 3-4 years i've used it. As long as you get your records correct imo it is also very easy to host and use, though Google keeps sending me TLS reports every day.