I am one of the persons behind https://www.torservers.net/ , a collective of non-profit organizations that run Tor exit relays thanks to your donations. :) I am not aware of any "arrests" anywhere, although some exit relay operators have been raided and their equipment seized in the past. I understand this might scare away some people from running exit relays. You can still contribute to the network by running non-exit relays.
Hidden Services use only the internal network and don't rely on exit relays at all. All communication is end-to-end encrypted, so all relays will only ever see encrypted content.
If you have less than a couple of Mbit/s of upload capacity, you might want to run a bridge. Bridges are especially useful for people in heavily censored regions, and only provide an entry point to the Tor network.
Hidden Services use only the internal network and don't rely on exit relays at all. All communication is end-to-end encrypted, so all relays will only ever see encrypted content.
If you have less than a couple of Mbit/s of upload capacity, you might want to run a bridge. Bridges are especially useful for people in heavily censored regions, and only provide an entry point to the Tor network.