Have you tried a factory reset? Hold in the pinhole at the rear of the router for at least 50 seconds and then release (the lights will flash while holding in the pinhole reset button after about 10-15 seconds) then allow 5 minutes for the router to reboot and re-sync the connection.
Also, if you're suffering from poor wifi you would probably be better of investing in a decent third party router, that way you can put the Virgin Hub into modem mode and let the router deal with all the traffic. This would give you better wi-fi coverage and if you go for the likes of a wi-fi 6 capable router you would get better speeds. There are loads of options from Asus, TP Link etc and seeing as the VM Hubs are well known for their lack of wi-fi capabilities you would be better of using your own equipment, especially if you are suffering from poor wi-fi coverage and speed. I know it's a case of having to spend money that you shouldn't have to, but it really is worth it and gives you a better all round internet experience.
You can also try this. Type http://192.168.0.1 into your URL address bar on your browser and login into the Hub with your chosen password or use the settings password on the Hubs sticker on the bottom of the Hub and set up the Hub with a new password. Then go to Advanced>Wireless>Smart Wi-Fi and tick the disable “channel optimisation” box and save settings. Then go to Advanced>Wireless>Security and rename the 2.4Ghz and 5Ghz network SSID's. Change them to whatever you like, for example JohnsVirgin_2 and JohnVirgin_5. You can keep the same wi-fi passwords or use one of your choosing, then click apply settings and restart the Hub. Your two wi-fi networks will now be separated and you can select whichever network you want to connect too, for example the JohnsVirgin_2 (2Ghz) or JohnsVirgin_5 (5Ghz). The 2Ghz one has a greater range but has a slower speed and the 5Ghz one has less range but faster speeds. Be aware that some older devices will only see the 2.4Ghz SSID but most modern devices with come with 5Ghz capability.
Also please be aware that all your previously connected wireless devices will need to be connected again to your new SSID's with you new passwords or your old password if you decided to keep them.
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Super Hub 4.0 (modem mode) - Gig1 Fibre FTTP - Asus RT-AX82U & Asus RT-AX56U with AiMesh setup
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