Modem mode is the best you can possibly do, it'll disable all of the routing features of the hub, leaving just the cable modem part - and it's this you can't replace. VM absolutely will not allow any third party equipment to be directly connected to their network, so anything you were to purchase and connect up simply wouldn't work.
Welcome back to our forums and thank you for your query regarding using modem mode.
We generally are unable to advise on third-party equipment however you may find the following link useful https://community.virginmedia.com/t5/Networking-and-WiFi/Advice-on-how-to-put-Hub-5-into-Modem-mode-...
Please let us know how you get on this weekend.
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I use my own Asus router, but I have left my virgin hub in router mode. My router works fine. I get a fairly good speeds so I’m unsure as to why people say you need to leave the Virgin hub in modern mode when using a third-party router?