The next reveal is Johto let's Go.

This is the whole schedule:

Reveal of Johto Let's Go

The Crown Tundra

Reveal of 4th gen remakes (Dawn Diamond and Dusk Pearl - DDDP - Giratina and Arceus are greatly involved in the plot) and next SwSh DLC

Release of Johto let's go + free DLC with a few older mons

Release of next DLC (part 1)

Announce of next gen

Release of DLC (part 2)

Release of DDDP

Release of next gen