8
7
6
5
4
3
2
a1
b
c
d
e
f
g
h
1…c5: push 2.d5

In your file, after 1.d4 c5, you played 2.c3 in 3 games, for 33%. The engine prefers 2.d5.

Recap: after Qb3 Nc6, why not Nc3 right away?