#1
3 cxd5 Qxd5 4 Nf3 cxd4 5 Nc3 Qa5 6 Nxd4 gives white an advantage in development.
A question about a queen’s gambit declined variation
I think 3. cxd5 nf6 4. dxc5 nxd5 might create a more equal position. After this black could try to play e5 or e6 to try to gain some control in the centre, and threaten the c5 pawn. after white’s next move, could black play something like na6 (unless it blunders something or white doesn’t protect the c5 pawn)to build pressure on the c5 pawn or is it just a bad idea to put the knight on the edge of the board?
#4
1 d4 d5 2 c4 c5 3 cxd5 Nf6 4 e4 Nxe4 5 dxc5 Qa5+ 6 Bd2 Nxd2 7 Qxd2 Qxd2+ 8 Nxd2
Is very good for white: a solid pawn up, but black has the bishop's pair.

I really dislike how white plays in these variations. Bad pawn structure.
This is better for white:
Qd3 was played by Mamadiarov
so I found a variation of the queen’s gambit declined 1. d4 d5 2. c4 c5 and I found some lines that could happen. do you think that they have a decent chance of occurring or have a good advantage:
Or maybe something more like this:
(with the intention of taking the c5 pawn)