5Ghz is faster but has shorter range, you could try it.
Netgear and TP Link don't make G.Fast capable devices. If wifi is the problem, as @Keith_Beddoe says, a different router probably won't help. You could try powerline adaptors if you don't want to run an Ethernet cable.
I remember reading somewhere that Openreach was using the Huawei MT992 for their G.Fast trials, if you can find one on the cheap, you can pair it with any third party router of your choice. Though this setup is more complex, it allows for more control since many routers support alternative firmwares like OpenWRT which have the benefit of allowing for better Wi-Fi range and bufferbloat mitigation.
The best solution though is to bite the bullet and wire your house with either CAT5e or CAT6 since this will give you the lowest possible latency and can support network speeds of 1Gbps/10Gbps respectively.