Do you have telephony? If so, you need to retain the Hub. If not, you can replace it with a suitable mesh as most will operate as either router or access point. But replacing it will pretty much limit you to Asus as other brands don't fully support Sky's authentication. In either case you generally switch off WiFi completely on the Hub U just use the mesh to avoid conflicts.
I currently run Asus XD5 in access point mode & cover a '70s three bed semi with two units, whereas I needed the TP-Link Deco M5s. I'm on FTTC though, so you'd have to check that they have the correct authentication.
You could also upgrade to WiFi Max at £4pm, which would give you the new Hub & up to three additional Pods. Plus side being that they'd mesh with the Hub's SSID to form a single network. Downside being the ongoing cost & if you change provider in future, you have to start again.
