There was a meme going round of a network diagram that layers a Chinese firewall behind a US firewall behind a Russian firewall so they can all block each other countries backdoors.

Not sure if you're joking, but both have already done so. And any US company is subject to secret orders forcing them to implement a backdoor if demanded.

They'll have a lot of work to do, if they want to catch up with the amount and rate of "hidden authentication backdoors" all those companies (and also Cisco) have. E.g. https://www.thestack.technology/cisco-hard-coding-passwords-...