Although you do open yourself to vulnerabilities in how you generate your random entropy—for average user, it might be worse than relying on a hardware wallet.

Although you do open yourself to vulnerabilities in how you generate your random entropy—for average user, it might be worse than relying on a hardware wallet. The safest play here for an average user is to just not buy your hardware wallets off eBay, as it seemed to be the case in the OP!