I have found that good quality usb-c cables, certified to 2.4A or more, solve many issues relater to power. I did not believe myself until I accidentally tested on a RPi4 a spare usb-c cable I brought for doing phone fast charging: mysteriously all my low voltage warnings dissipated.

I'm sure they would - usb-c has a good power rating. It also confirms my suspicion that the standard RazPi power power supply has issues on 220VAC mains.

The one item using serious power is an ssd which goes from usb-A, via a short lead to the unusual usb-3.x lead sold with the drive, (kinda 2 plugs in 1) and there isn't much scope for getting clever with that.

Those double plug USB3 leads have a white & a blue plug, at least mine has, sometimes it will work with just the blue plugged into a regular computer, but it always needs both plugged in on my RPi4 - & I believe, (from what I've read), the power cable uses 18gauge wire, (if that helps).

My 2 usb-3.x plugs come as one, so I've no choice about which to plug in. I'm becoming convinced the standard RazPi power supply is low in the much larger section of the world that uses 220V mains, not 240V. Otherwise, problems would not be so widespread.

Back in the day, lack of width on a tv was often traceable to low mains supply, because mains varies more than people like to think. ±10% is for the birds.

Ok results are in.

When my lacklustre hub finally arrived I pulled up a chair and one-handedly attacked the setup largely positioned by others. The hub works, the power warning is gone, and I have line-of-sight to my wifi keyboard/mouse receiver which seems a good idea.

I have to wonder at an Ebay seller who sold this on the 19th, revised the delivery date without notifying me, and posted it on the 30th March. But with Covid and Brexit going on I have to cut him/her/it some slack.

OK, final results are in.

My new setup has a powered usb hub taking the disk and keyboard/mouse wifi receiver. Apart from the disk, The RazPi only has a wifi dongle (100-150mA) in usb, along with the powered hub.

Lablists have a photo up of what you get, but the actual power supply is different to the one in the photo. It's probably some cheapo thing from china. The RazPi is not overclocked. With <2A load, the RazPi 4 is still complaining of low voltage.

I am in the hugely irritating position of having the know how to track these things down, solder, bodge and intelligently diagnose exactly what's wrong, but I don't have the hands to implement my skills, as one hand is paralysed. So I'm buying the power supply I should have been given but wasn't. After living with this for a while, I'm a month out of warranty on my purchase.