It is quite strange that these peripherals still don't have PD-usbc for power input.My conclusion is that what I was looking for does not exist.
In fact I have bought the Sonnet Echo 5. So I now have two power supplies, 100W for the Echo and another 140W for the MacBook, which is not currently used. This seems both a waste of materials and money (not to mention the MagSafe port) as the one with the Echo is not a cheap looking unit.
But my point remains; I did not need another power supply, simply a way of routing power directly to the peripherals without involving the MacBook's power system - I believe it is by using the MacBook for power distribution (especially in the heat of this summer) that my last MacBook only lasted just over two years and now has faults both in the battery and in the SMC.
So whether I need a hub or a dock is irrelevant. Is the Echo 5 a dock or a hub? It has power but a minimum of ports.
There is definitely, in my opinion, a market need for a powered hub (or dock) that uses the Mac PSU. A drawback of the Echo (and any other similar unit I believe) is that is won't work passively.
Maybe there are some licensing fees?