On any USB hub that works correctly, bandwidth is only assigned to devices that actually use it - that means that a USB keyboard will not use more than a few kilobits per second and won't slow down a fast device on the same hub.
The calculation has a result of 8.884 gigabits per second, so there should be about 31 Gbps left over for any other devices.
I think the Echo 11 is probably a good choice - there are some less expensive TB3/TB4 docks, but they seem to be designed for Windows devices only so there might be some driver issues on macOS. I have no idea how expensive the TS3 is in Australia, but in Germany it costs 50% more than the Echo 11 and I don't think it's actually 50% better.
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