Hosting a signal proxy is probably not a big deal if you don't plan to ever travel to countries that have blocked Signal, but I would strongly advise against hosting a Tor exit node as a private individual. Tor is used for criminal activities all the time, and unless you have plausible deniability as an organization (and a good lawyer), it will be blamed on you personally.

Signal Proxy is fine, and it's helpful for people who live in countries that block Signal. I ran it during Iran revolution. It's only a nginx forward proxy.

Tor exit relay is a big no-no since you may expose yourself to illegal content. But you can run a relay without it being an exit node.

You don’t have to be an exit node to help; Have a look at setting up a Tor Snowflake proxy. I haven’t looked at Signal proxy, but I’ll check out that blog post.

If only the Signal Foundation made it as easy to set up a Signal server and connect Signal clients to it.