But dont you have your services on the same IP and different ports? If thats the case you will also need reverse proxy like nginx. So DNS server will point your domain name (you can just make a name for local use) to your server IP. Then reverse proxy can point each name to a specific IP and port.
Its that simple to use different IPs just with DNS server:
DNS server
192.xxx.x.47 -> plex.yourdomain.xyz 192.xxx.x.53 -> snapdrop.yourdomain.xyz
But dont you have your services on the same IP and different ports? If thats the case you will also need reverse proxy like nginx. So DNS server will point your domain name (you can just make a name for local use) to your server IP. Then reverse proxy can point each name to a specific IP and port.
Reverse proxy
192.xxx.x.47:32400 -> plex.yourdomain.xyz 192.xxx.x.47:8080 -> snapdrop.yourdomain.xyz