So... breakthrough
. Camera clocks are inaccurate
. It's 2021 and we're still off by 15 seconds per month. Well in my case, 11 seconds in less than 12 hours.
Still inaccurate clock timecode works... Importing all clips (3 cameras) by their timecode puts them in the correct relative space. Drag all clips at once - per camera - to the single loud 2-peak dog clicker ($5.26) spike, in whichever clips has it and all are instantly aligned.
Just be sure to click (one time is enough) when all cameras are running.
After the steep learning curve (I'm a novice), this process seems so much easier than using a tentacle.
StarMark Clicker Dog - super loud and fun to use.