Then this video card draws up to 550W if you calculate your remaining parts where:
CPU: 105W
HP OMEN motherboard: 65W to 230W
(Depending on the installed fans, CPU cooling and other external components) always calculate for safety at least 150W consumption

So in short 550w+105+150 = 805W
Also, what grade is your power supply marked with? Bronze, Silver, Gold or Platinum ?
Because your PSU says 750W but if it is below platinum grade it means that part of the power is lost and therefore delivers less than the marked power

I would recommend changing your power supply to at least 850W but 1000W is better.
Above all, bear in mind that gold and platinum are the best in terms of power consumption because they lose less power.

Remember that for new video cards you will need a power supply with a power socket (new power supplies) or 4 sockets with 8 or 6+2 pins