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If you're going to set up something and then not use it, it's not going to help any. a caching or better, a forwarding dns server is pretty useful for any network. you could look up how to set up bind9 or pihole (not as involved but it doesn't teach you as much). then there is something like pfsense which can be your router if you have a spare computer and can buy a 10-15$ network card and using it/setting it up has taught me the vast majority of how networking works (to be fair I did look up a lot of things cause I'm a nerd). a thing that is as easy as the dns server is running some sort of service/server in a virtual machine and then using it, maintaining it and monitoring it. you can learn most of the basics that way (at least in my opinion).
clarification while I do offer my views and opinions, I consider myself a beginner in this area, if anyone with more knowledge jumps in and corrects me, I am more than thankful
