Pre-builts are near-universally trash from every angle you can possibly look at them for, particularly when it comes to building a top-end PC.
Too many issues: unequal components bottlenecking each other, bad software setups (BIOS, OS, bloatware, auto-clocking), poor cooling solutions throttling the hardware, low quality components (such as PSUs), and they can lock you into certain configurations that cannot be upgraded without systemic replacements.
Sure, you can potentially research into a decent one if you have money, but no knowledge for building a PC, but damn is there so many bad ones out there that you’re highly likely to be scammed. Gamers Nexus reviewed a $6600 one that was quite disappointing.
PCpartpicker is everyone’s friend when it comes to builds.