An option which covers a bunch of different experiments: set up PiHole on it (despite the name, it doesn't need to be run on a raspberry pi) then set up a persistent VPN, for eg wireguard, or whatever your router supports, to it from where you are, and then setup your router to use it as your DNS server for your vlan.
Its a relatively simple set of tasks, but they build a good grounding for anything else you end up wanting to run on it.
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