My astra does not start

Good day, my name is Juan Carlos, and I have a 2004 Astra automatic 2.0.
A few days ago, the air duct that runs from the filter to the throttle body was replaced because it was broken, and the intake was cleaned. It was also slow to start, but it would start on the second or third try, sometimes with a little help from the accelerator. The fuel pump would activate when I turned the ignition on, but sometimes it wouldn't. Normally, it started on the first try.
The strange thing is that yesterday it started right up, but today it wouldn't start at all. After trying more than 20 times, I gave up.
The symptoms are: the fuel pump is working, but once the ignition is on, it doesn't start on the second try; it can vary. The car seems like it wants to start but can't. The battery is good, and the starter motor is fine. Another thing is that once the car is warm, it starts right up. I always have trouble starting it from cold.
I hope you can help me, and thank you for your time.

On a cold start, it could be a problem with the temperature sensor. If you want to rule out the fuel pump, try connecting a direct wire to see what happens. Could it be flooding due to excess fuel? Once it starts, do you smell a strong smell of gasoline?

Hi.
I could tell you about an experience I had with a 1.4 Astra.
It had a similar problem to the one you're describing. Sometimes it would start, sometimes it wouldn't; other times it would start right away, but if you turned it off, it wouldn't start again. Well, I can tell you that the problem might be the fuel pump
because what I did when the engine wouldn't start was directly power the fuel pump with battery voltage, and the pump wouldn't work. So we replaced it, and it never failed again.
Good luck...