There are switch on/off adapter cables like this: https://www.amazon.com/CRJ-24-Pin-Switch-Jumper-Sleeved/dp/B01MSY4966/ref=sr_1_8?keywords=power+switch+atx&qid=1684340335&sr=8-8
Which use even 3 different thick cables to connect to the ATX-24-Pin cable.
So I think it will not work with just the smaller cable.