With horrible pc parts price I bought this Office PC with a Asus Prime B360M-K to upgrade as a gaming pc but the chiniese GTX 1650 Low profile I bought does not boot sometimes. It gives 1 long beep and 3 short beeps gap and another beep. card fan does spin all the time.
Give us a close up of your motherboard here.
Also, try booting without the optical drive plugged into anything. It’s useless anyway and it might be just enough of a difference in power to get you booted reliably. If that does work though, I wouldn’t be surprised if you see crashes when you throw a graphics workload at your card and it tries to draw its full power.