Self hosted services with SSL cert - Lemmy.world

So, I have a few services (Jellyfin, Home Assistant, etc) that I am running, and have been acessing via their IP’s and port numbers. Recently, I started using NGINX so that I could setup entries in my Pi Hole, and access my services via some made up hostname (jellyfin.home, homeassistant.home, etc). This is working great, but I also own a few domains, and thought of adding an SSL cert to them as well, which I have seen several tutorials on and it seems straight forward. My questions: - Will there be any issues running SSL certs if all of my internal service are inward facing, with no WAN access? My understanding is that when I try to go to jellyfin.mydomainname.com [http://jellyfin.mydomainname.com], it will do the DNS lookup, which will point to a local address for NGINX on my network, which the requesting device will then point to and get the IP of the actual server. - Are there risks of anything being exposed externally if I use an actual CA for my cert? My main goal is to keep my home setup off of the internet.