Unlike most here, I'm not as concerned with opening things up. The two general guidelines I use are 1. Is it built by a big organization with intent to be exposed, and 2. What's the risk if someone gets in.
All my stuff is in docker, so compartmentalized with little risk of breaking out of the container. Each is on it's own docker network to the reverse proxy, so no cross-container communication unless part of the same stack.
So following my rules, I expose things like Nextcloud and Mediawiki, and I would never expose Paperless which has identity documents (access remotely via Tailscale).
I have many low-risk services I expose on demand. E.g. when going away for a weekend, I might expose FreshRSS so I can access the feed, but I'd remove it once I got home.