The ones I generally saw were no-name mechs about the size of an acorn. They had a serious stupid problem though, because there was no strain reliever on the cord base and the bottom hole the cord came through was sharp it would cut into the cord and they died in a few weeks. A 5¢ strain relief grommet would have stopped that. There was one that didn’t have that issue. It was $30 though and still didn’t have a pcb in it. The one in the video I haven’t seen. It doesn’t look like it has a pcb either though. Seems like a usb would be easier because then you could turn your computer or a battery bank into a vape too. It does seem to have a decent cord with strain relief though. So also a mech.
Easiest way of all would be just put a USBC port on the bottom of the handheld bit and source a USBC cord that has strain relief. Cheap, simple, universal. I don’t understand why it wouldn’t just crush. DNA use to do a really narrow board that would work well. USBC delivers insane ampherage though. More than enough to run a pcb. Just have to do something higher than usb 3.0. 3.2 would do it I think.