Honestly, 750W is playing with fire given that 13700K power draw. In my experience over the years, those transient spikes from the 40 series are no joke. Even if the calculators say you are okay, you have to remember that a CPU under load plus a GPU spike can easily trip the OCP on a unit that is already working near its peak efficiency, especially during intense gaming. I have tried many setups and personally never feel comfortable pushing a PSU past 80% capacity. Since you are on a budget but need reliability, I would seriously consider swapping that unit. The Corsair RM850x 850W Gold Modular is basically the gold standard for these builds and will give you that extra breathing room you need without breaking the bank. If you want to be extra safe and ensure longevity for future upgrades, the be quiet! Straight Power 11 1000W Platinum Modular is an absolute beast that runs dead silent. I have used both in client builds and they handle high loads perfectly. Dont risk your hardware crashing mid-game. It sucks to have to buy a new PSU now, but troubleshooting a system that randomly shuts down is way worse. Grab the 850W or 1000W model before Friday and you wont have to stress about it again.

^ This. Also, I honestly think you might be okay if you undervolt, but are you planning on overclocking that chip at all? If you push that CPU, you'll definitely want more overhead. I personally love Seasonic Focus GX-850 type units for peace of mind if you end up upgrading. Just stick to reputable brands like Seasonic or maybe EVGA and you'll be golden, but honestly, try the current one first!