This is an older feature, common for example in Insteon outlets and zwave gen 3 devices, but since dropped by most manufacturers since it’s very confusing for consumers. You basically have to turn the switch on twice to make it work.
It’s called “load sensing” and is still a parameter option on some devices.
That said, it doesn’t apply to the use case being described in this thread. It’s really intended for table lamps so that you can turn them on with the switch on the lamp even if it was turned off by the smart outlet. So as to allow you to have a manual switch even though the device is plugged into a smart socket.
But in this case being described in this case, the OP is trying to avoid the use of a physical switch all together. Very different set up.
(BTW, I forgot to mention earlier that the reason I thought controlling the socket rather than altering the cord might be an option is because I assumed you had to be able to get to the socket in some way to plug-in the devices to begin with, and I had imagined that the reason you didn’t want a plug-in pocket socket was because there wasn’t physically enough space for one. I didn’t realize you were also trying to address the issue of not just cutting the power.)