If you’re open to a suggestion from a lurker, I would suggest…
One thread per week / Office Hour.
The thread can go up as soon as you have a topic/participant/date. If you know four weeks ahead, you can create the thread four weeks ahead.
Suggestion: Use a standard title format so past streams are easy to find (Community Office Hour 29 March 2022 - Santa Claus and Webkit).
The thread allows you to organize the life cycle of the Office Hour: Preparatory input, announcement/pin, stream links, and follow-up.
Discord has an Announcements category as well as Pinning. Use both. For example, two weeks before the Hour, move the thread from the UbuntuOnAir section to the Announcements section. (It does not change the thread’s URL). AND pin it for the two weeks. A few days after the Hour, unpin and move it back. I’ve noticed that Office Hours seems to get a lot of more views in the 72 hours afterward than it gets during the live stream, so keep the Announcement up for an extra few days.
If a guest brought up some links during the Hour, might be best if THEY make a post in the thread adding those links. It gives them a chance to engage directly with others on Discourse, which seems one of the purposes.
The goal here isn’t to make more work for you. It’s to organize your existing work so that it’s easier to find by more people.