Yup, I don’t trust it to not install a rootkit on the BIOS or something. Buy from reputable companies, and if you get a prebuilt PC, you’ll probably want to reinstall Windows to get all of the adware off. If you don’t use Windows, you’re probably fine with just buying from a reputable vendor.
That’s what I’m always most paranoid about - buying storage and having some bad actor insert malicious code through unusual means.