I read this as: The Air and Mini will be switching to the 3nm architecture, but the iPad Pro line is not yet ready. So they’ll wait on all of it to avoid sabotaging their own lineup.
The Vision Pro is also set to launch with the M2, making the M3 likely delayed in all products. So the iPhone is going to get the 3nm and everything else is in stasis.
I would be glad to be wrong on this timeline, just speculating based on what we have heard to-date. Holding out hope that the Mini will receive an update if they keep it on an A-series chip.