I have just thought of a really good ‘get out of jail’ card for the production team just incase they cannot get a (Seven of Nine) spin-off series, or if there is a delay in doing so.
My money is on delay. Paramount is already clearing $280m annually on the live action shows alone. Probably another 3 million or so over Lower Decks and Prodigy ($20k per minute of animation + paying the voice actors etc).
Stuck in the development wilds is at least the Section 31 show with Michelle Yeoh as the lead, and the Star Fleet Academy show which, if a 31st Century show as rumoured, will have Mary Wiseman at the helm in charge of the entire reformed Academy.
It's also fairly hard to see where it might fit during the year, as the main aim on Paramount's part is to keep a Trek show rolling almost all year round and to get us to keep those subscriptions up. It "only" costs $100/£82 a year, so needs a fair few of us pretty much permenantly subscribed to make it profitable. Would we see more audience fracutre? Fans tiring as we're now seeing with Marvel? It's a very hard thing for them to consider as well. Kurtzman's strategy has been to approve fairly radically different shows to appeal to different audiences. Which so far seems to work pretty well.
Kurtzman himself apparently has roadmap somewhere in his office/the Trek unit since 2020 which runs to 2027, if we go by the 7 season format for Trek shows we normally get, then Discovery's final season will come in 2025, meaning new shows would have to fill in that space.
So who knows, it might turn up quickly or it might be a few years down the road. Ryan and Hurd are only in their 50s and seem fine and fit compared to most people in their 50s I know, so its not like a couple of years is going to make them suddenly too old to do the roles.