Interesting use case!
I do believe that you would be better served with a few changes:
Move ban expiration to a dedicated custom topic field
This will allow you to validate that every ban has an expiration when a new topic is created, and will make querying for expired bans a breeze.
You could also use our Introducing Experimental Form Templates, which also give your programmatic access to a specific data in a topic.
Add /filter custom filters
With the custom field or form template, now it is easy to add new /filter filters like expired bans, archived bans, etc. Those would then become your moderator main work lists, and they can be added to the sidebar for ease of use.
Automate bans as a whole?
Final piece would be to Discourse to automatically create the bans on Roblox and Discord whenever a topic is created, and also to automatically remove the bans when they expire.
This is kinda easy to do with a recurring job and API access.
If you have a Set up a local Discourse Development Environment, then you can even pass my post here as a spec to Claude Code and it will build it in minutes.