TL;DR: Stick with a high-end air cooler. Liquid AIOs are fancy but honestly just add more points of failure and potential leaks that can ruin your expensive i9. I had a nightmare experience with a pump failing years ago and honestly, never again. For a first-time build, you want simplicity. The Noctua NH-D15 chromax.black Dual Tower CPU Cooler is basically the gold standard here. It is big and ugly, sure, but it cools better than half the liquid kits out there and won't leak on your motherboard. Installation is super straightforward compared to fiddling with radiator mounting and routing tubes. You just bolt it on and you're good. If you really want something that looks a bit sleeker but still relies on air, check out the be quiet! Dark Rock Pro 5 120mm/135mm PWM Fan, which is whisper quiet. Unfortunately, these giant air coolers are a pain if your RAM sticks are super tall, so double check your clearance before you buy. I dont trust those liquid tubes for a beginner build; if you bump them wrong or get a bad unit, you're looking at a fried system. Keep it simple and focus on getting the build done with your nephew so you can actually game.

Re: > TL;DR: Stick with a high-end air cooler. I gotta say, I agree with that advice, but if you want air, the Noctua NH-D15 chromax.black Dual-Tower CPU Cooler is basically the gold standard. It's huge, so what case are you using? That i9 runs really hot, so you definitely need to check if it fits. Just make sure you dont overtighten the screws or you might crack the bracket. You got this.

Adding my two cents, honestly, dont overthink the liquid vs air debate. I was in your shoes a few years back, terrified of frying my first high-end build, and I ended up picking the DeepCool AK620 High-Performance CPU Cooler 260W TDP and honestly? I have no complaints. It keeps my chip cool and I never have to worry about a pump failing or leaks. If you want something that looks a bit sleeker but performs just as well, look into the Thermalright Peerless Assassin 120 SE Air Cooler. It is honestly a steal for the price and super easy to mount, even for a beginner. Just make sure your case has enough clearance, those things are basically bricks. Trust me, keep it simple and you will be super happy with the results when you fire it up on Friday.