Look HODLers, we have to find a way to teach people how to understand hardware wallet safety principles. I propose some simple to understand analogies. People like to learn through idioms you know. I'll give it a go.
Getting a used hardware wallet is like re-using a condom. Completely defeats the purpose.
Buying a hardware wallet from any third party other than the manufacturing company directly is like buying medicine from the vet store. Might be cheaper but could risk costing you literally everything.
Buying a hardware wallet with a sealed non-transparent casing is like buying a car and asking to paint the windshield with a thick cost of vantablack. You need to see what's in there so you can compare it to the original circuit designs and verify it has not been tampered with.
Buying a hardware wallet from a company that doesn't have a bug bounty program and/or doesn't encourage serious research to hack-proof their products is like making your money a guinea pig.
Putting your money in any wallet with closed source software is like putting it in someone else's lock box. You're probably not the only one with the key.
Getting an already etched private key store metal card is like finding a key in the middle of the street and asking the locksmith to design you a lock for it to put on your main house door.
Feel free to reiterate and have fun.

A funny AI image I promoted for your inspiration.