How to Identify Thunderbolt Compatible USB-C Extension

I have an old Apple Thunderbolt Display that I’m using with an M1 MacBook Pro via Apple’s Thunderbolt 3 to Thunderbolt 2 adapter. The USB-C connector on the adapter is quite short and so I’d like to extend it. While I’d happily accept a recommendation for a specific USB-C extension cable someone's used in this way, my real question is how one might identify the correct cable. I’ve done some Googling around and ordered two extensions from Amazon that claim to be Thunderbolt 3 and 4 compatible, but neither works in practice. USB-C extension cables in general seem to be a bit of a speciality item (which I get) so none of my reputable dealers sell one which makes me wonder if I'm missing something. Is there a fundamental incompatibility here that makes this impossible?