I think it’ll make more sense to have a gen 10 release to get to 30 starters for the 30th anniversary. 
Weren’t the 25th First Partner Jumbo cards also released per gen over the course of the entire year, starting with the Pikachu & binder and three Kanto starters?
I’m gonna predict we’ll see gen 10 leaks on Pokémon Day (Feb. 27th, 2026), and then gen 10 starter Jumbo cards near November/December, since November was also the month most other gens were officially released. Just my 2c.
Greetz,
Quuador