The inherent ability to transfer data on a standard USB-3 "SuperSpeed" cable is 10 G bits/sec, FULL duplex (both ways at once). In certain demanding cases (but generally NOT on Apple-silicon Macs) the two pathways can be "turned round" so that both are momentarily transmitting the SAME direction, for a burst up to 20 M bits/sec. This does not appear to be a factor here.
When you mix multiple devices on a USB Bus, sometimes the other devices connected can reduce the speed of All devices. Exactly how this plays out depends on the details of implementation of USB on the Host device.
------
In your first example, the FIRST Realtek 4-port USB-3 Hub (¿built into the drive enclosure?) is able to maintain its 10 G bits/sec speed.
it appears the the drive enclosure features ONE (or possibly TWO) drives in a special slot behind ONE Realtek 4-port Hub, In addition, a second Realtek 4-port hub is organized in a way that is subservient to the first 4-port Hub, supporting more drives. It is not at all clear what is happening for subsequent devices, because they are not shown in detail.
Next, a THIRD 4-port hub is shown, supporting a 4th 4-port Hub, supporting a MyBook 25ED drive and a 10./100/1G/2.5G Ethernet port.
Nominal USB-3 speeds of 10 G bits/sec each direction is about 1,000 M Bytes/sec after encoding, and you can expect to realize (after overhead) about 2/3 that much in practice, or around 600 M Bytes.sec. This is the Highest Possible speed supported.
-------
in your second example, the FIRST Realtek 4-port USB-3 Hub (¿built into the drive enclosure?) is able to maintain its speed at 10 G bits/sec. Next, a second Realtek 4-port hub is organized in a way that is subservient to the first 4-port Hub, but no drives appear at this level.
the Third 4-port hub here has a different Product ID. It is at the same level as the first 4-port hub, but its speed is USB-2 speeds, and it is called a 4 port USB-2 Hub. nothing connected to that Hub would be expected to achieve higher than USB-2 speeds.
Nominal USB-2 speeds of 480 M bits/sec each direction is about 48 M Bytes/sec after encoding, and you can expect to realize (after overhead) about 2/3 that much in practice, or around 32 M Bytes.sec. This is the Highest Possible speed supported.
I do not know what you have connected to what, and whether all these Hubs are built into products or stand alone Hubs. but based on this information, your hardware appears to be operating as expected.
if you are NOT using separate stand-alone Hubs in your setup, you might be able to get more information about how these built-in Hubs are expected to operate by contacting the drive enclosure maker.
Readers would love to hear what they have to say!
