Build it. You can get exactly what you want and know you put everything together so nothing is loose or misplaced. I originally picked up a GI model but ended up replacing LITERALLY every part, except the buffer tube, buffer retaining pin, and the take down pins. Everything else got swapped with super lightweight options. I'm aiming to go below 7 pounds unloaded with no optics lol.
You just need some headspace gauges to make sure your bolt goes with your barrel, and a torque wrench to tighten up the barrel nut to spec.
Super fun and rewarding to build for sure! It will be a bit more expensive to build it yourself if you get higher end parts, but you end up with something you want EXACTLY.
If you go with on sale or less crazy lightweight stuff, it will be cheaper to build.