Opening for defensive player

I recommend specifically the Delayed Alapin, for one simple reason. It reduces Black’s strength and number options and increases White’s.

As far as 1. c4, play for the Reversed Taimanov Sicilian against 1… e5, Ultra-Symmetrical Fianchetto against 1… c5, and 2. Nf3, g3, or d4 transpositions against any of the more passive of Black’s options.

I do prefer to put pawns in center of board more now like 1 d4 2 c4 but if looking for solid counterstrike opening as White the Nimzo-Larsen 1b3 is worth a look

but by playing the delayed alapin you miss out on the open sicilian, which is not what you want to do as you are getting better

I don’t fully agree. The Delayed Alapin is almost as strong as the Open, but much more importantly in this circumstance, it can be played much more closed and positional, especially compared to the Dragon, Najdorf, Scheveningen, and Classical, which are the 4 main d6 Open Sicilians.

If the OP was looking for raw strength or improvement, I would probably recommend the Open, but not in this case.