Selfhosted

Really the first issue is your IP address. How does your ISP hand out IP addresses IPv4 and/or IPv6?

If you have an ISP that gives a static block of IPv6 addresses that simplifies things immensely. But also consider that many legacy, monopoly ISPs have not implemented IPv6 for their customers, especially in the US, and so domains without an IPv4 address aren't accessible from people's homes that use those ISPs. But it means you could assign static IPv6 addresses to each service if you wanted to and add subdomains for each. Then you just need to deal with security on that system.

Otherwise you'll likely need to deal with dynamic DNS. If your router and your domain registrar's DNS can work together for DDNS that's ideal. For example, my OpnSense router updates my cloudflare registered domain directly when my ISP changes my IPv4 address (I have one of those ISPs that doesn't assign IPv6 still but I don't have any choice if I want > 5-10Mbps upload speeds).

Then you need to deal with routing. The best way is with a reverse proxy like Caddy or I actually like Traefik a lot because it works well with my complex setup with docker and kubernetes among other things. Basically your router needs to route all the inbound traffic on the appropriate inbound ports to the reverse proxy to it to then route to the appropriate service based on the subdomain and/or port of the request.

Once you route the subdomain to the appropriate service you need to deal with security. Once a service is exposed, it's going to eventually start getting hit by bots trying to access it. Best to implement something like fail2ban to stop them from wasting your processing power with failed logins and 404 errors and such.