Confused about QGD Ragozin defense
at least it makes it easier for white to prepare as black has already committed to d5 here. for example if white plays the 4 e3 nimzo he doesn't have to study the c5 lines or the b6 lines without d5.
1. d4 d5 2. c4 e6 3. Nc3 Bb4 is not unaccurate, it is frequently played by GMs especially in recent years. It was previously thought that after 4. a3 or 4. e3 Black would have commited too early with d5 in case the doubled pawns arise with Bxc3+ bxc3, therefore allowing White the Botvinnik pawn roller structure with cxd5 (it was also not clear if Ne7 would be more useful than the Nimzo Nf6 move), but in computer days it's not the end of the world.
Looks like the newer engine versions have caught up with human opening theory. 3. ...Bb4 signifying the Nimzo-Indian Defense is now considered the best move by Stockfish, and 4. ...Bb4 signifying the Ragozin Defense is considered the second-best move by Stockfish with an evaluation very close to 0 or +0.1.