Even though each game is a player driven RPG, there’s a canon “through line” of major events from 1 to 2 to New Vegas. 3 and 4 are set far enough away or in a different enough period of time that the plot impact is more minor.
Personally though, I hope this is less of an adaptation and more of a “side stories in the setting”.
From what I’ve read about the series it’s actually set 4 years after Fallout 4 events. So it’s more “side stories in the setting” rather than straight up adaptation.