if you look at the release dates for the pokemon games, you see:

1. 3 years between every mainline game
2. 1-2 years between each expansion (e.g. emerald, platinum)
3. 5 years between each remake

Now, Let's Go Eevee/Pikachu was released 19 years after the original, and the time between originals and remakes increases. (8 years for FRLG, 10 for HGSS, 12 for ORAS, and now 15 for BDSP.)

Assuming at least 19 years before Pokemon Gold / Silver Remake Remake, and assuming at least one Pokemon release per year except for 2022, we can determine:

1. 2023: New mainline game
2. 2024: Mainline DLC / expansion
3. 2025: Pokemon Black and White Remake
4. 2026: Pokemon Gold Silver Remake Remake, and a new Mainline game

mark my worlds... i am a gaming industry expert.