You can get two Hubs, but that will mean two accounts and two payments to VM.
However, can you post the power levels and network log from the Hub. Also setup a BQM here www.thinkbroadband.com/ping to monitor your connection.
As for the powerline adapters they rely on the house wiring to work and can cause latency.
If you need a better connections, either run Cat 6a ethernet cables or setup a Mesh system.
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