I tested a few different generic ones and found this one actually works; sold by Recordfoto
https://www.amazon.com/Bestshoot-Wireless-Bluetooth-Shutter-Smartphones/dp/B07BLWY9BP/ref=pd_ybh_a_1?tag=vcfboard-20&_encoding=UTF8&psc=1&refRID=8H0W62C4NMY05CWMBXT1
BTW I saw this is first done here: https://www.youtube.com/watch?v=2S1j7vdMX5U
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