I also don't think even a few feet of cabling, including the cables inside a PC case, is likely to cause any issues unless they're the cheapest thinnest cables that could be found, so having a cable running from the top of a desk down to a PC case on the floor shouldn't be a problem.
I have indeed found problems with cable length on USB3 file transfers into USB-A ports.
This happened when transferring RAW + JPG files from 64GB CF and 128GB UHS-II SD cards in Kingston FCR-HS4 readers. When I switched from long thin USB3 cables to short thick 30cm (1ft) Startech cables on the readers, Free-File-Sync stopped reporting file corruption errors when perfoming bit-by-bit comparisons. The CF cards read back at 130MB/s and the UHS-II cards read back at 180MB/s when copying to M.2 NVMe. Long USB-A cables caused file corruption on my laptops.
I've had similar problems with fast portable SSDs at home when using long USB-A cables connected to the front panels of several desktop machines. For more consistent transfers, I use the short 20cm or 15cm USB-C cables supplied with some portable SSDs (e.g. Crucial X6 or X9) and connect the drives directly to the rear panel (not the USB-C port on the front panel).
Admittedly there's no way a spinning hard disk will reach the nominal 1,000MB/s sustained transfer rate of a Crucial X9, but I do have some 8TB Toshiba hard disk drives which start off at 250MB/s on the outermost tracks, dropping to 120MB/s on the innermost. I'd be wary of using such drives in a USB3 caddy with a long USB-A cable. Just me being cautious.
The file corruption when transferring photos from reader to laptop was insidious and only noticeable after checking the image files visually at a later date. On festival days when I shoot more than 1,000 photos, I don't have the time to check every pair of RAW + JPG files thoroughly. Instead I make three copies on different drives and run bit-by-bit file comparisons, before wiping the CF and SD cards for the next days shoot. After formatting the cards and re-using them, there's no chance to recover any files corrupted during transfer.
If file corruption during transfer occurs at home and I still have the original data, failed copies are little more than an annoyance. All I can say is "once bitten, twice shy". Paranoid maybe, but I stick to short cables.
Using hubs or even just straight external drives if you're moving around a lot or on an unstable surface like a bed a lot is probably one of the least advisable environments for those.
The only reason for using unstable lashups on a bed is because some guest houses in remote areas do not come with a desk or a table. In some rooms you don't even get a chair and the bed is the only flat surface. You learn to make do.