No.
You must realize that passthrough is extremely rare, found in maybe 2% (at most) of consumer recording/playback devices. And most of those are higher-end, not junk from thrift stores, nothing ever sold at Walmart or
Amazon.
You cannot take any random device (camcorder, DVD recorder, toaster, whatever), and expect it to have passthrough.
In an analog videotape capturing context, "passthrough" refers specifically to the ability for a signal to pass into a device with added TBCs/filters, while utilizing said TBCs/filters, yet not requiring playback on said device. Normally, devices only engage TBCs/filters while playback within the device, not from an external signal.
Hi8 camcorders don't have passthrough. And you are correct, as I'm not aware of any that have any inputs.
DV camcorders (mostly) don't have passthough. A few better cameras do engage mediocre/weak line TBC for external input. However, it comes at a price, because the analog input signal is converted to lossy blocky DV compressed output.
Digital8 is just a DV camera, using 8mm Sony tape. But it's more like Hi8 than DV in this regard.
So what you're reading is a mishmash of nonsense and bad understandings of gear. With all the info we have online, and have for decades, it's really quite sad.
Aside: Sometimes I feel like the video capture community is regressing to child-like naivety when it comes to video. We weren't all this ignorant 10/20/30 years ago. I blame skimming, and not actually reading. Or reading/watching whatever telephone gamed (Youtube/Reddit) BS people come across, and not vetting it or the author. Limited character Twitter/etc platforms didn't help, as you can't teach complex topics in the 2 allowed sentences (most of which is mind vomit anyway). NOTE: This comment is admittedly a bit harsh, but it's not to you directly.
