When I was rebuilding my CyberpowerPC prebuilt I found that they:
were charging premium prices for CPU coolers and case fans literally from 2013 (bought my system in 2021).
hadn't removed the plastic sticker on the heat sink before installing it
Installed one of the CPU cooler fans backwards.
Hooked the CPU cooler up to the wrong fan controller on the mobo
Used a PSU so shitty that my ram literally couldn't even enter XMP mode, it was manually set (incorrectly) in the BIOS.
When I tried to RMA a part it took almost 3 months and I ended up having to literally email the CEO to get my support request escalated to someone who would actually help me
Probably some other stuff I'm forgetting right now.
Had to replace: Case fans, CPU cooler, PSU, various bits of wiring/cable extensions, and a solid side panel door for my case which was somehow bent when I received the machine.