Hi - looking for advice please.

I currently have a tp link ac750 with a Vodafone data only sim.

we use this because the only broadband available is BT at about 2mbps. Promised fibre never seems to reach our part of the village.

We use it for WiFi to Childrens lap tops, for watching tv via roku (there is no cable, satellite or digital tv reception) and downloading games to sons play station.

4g to my mobile phone (also Vodafone) is reasonable.

we have found it has started buffering occasionally but for the last 2 days has been absolutely terrible. Vodafone say it is not then but I'm no expert - could it be the router? Any advice gratefully received