I don't expect a Let's Go Johto, and I really don't want it. Not only because I didn't enjoy the game but because that would mean, Masuda wasn't telling the truth (lying) back in October 2019.
Also, if I recall correctly, back in an interview in 2018, Masuda was saying the plans for the future of Pokémon was the introduction of more Spin-offs. So I expect they are going to break the formula of: "new generation, remake, new generation, remake,..." that they kind of followed, and make more collaborations projects with other companies.
Anyway we can sense this announcement is the Tencent X Pokémon collaboration.