You are getting ~1GB on ethernet - so the connection and Hub is all good - leave the attenuator on.
You will never get anywhere near 1GB on wifi without using a wifi6 router - the Hub4 does not have wifi6. Someone more tech savvy can explain what you can expect - IIRC its about 650mbps
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John
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I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.