I currently use deco s4 but have a large house and some areas are still fairly slow on internet.  When im gaming online sometimes the signal drops out if another member of household is streaming on netflix or instagram 

I have just ordered trooli brandband for 500 speed (currently max 60), it has wifi6.  My brother needs his Deco S4s back which should i buy without needing to spend a fortune (as when i borrowed them it was a game changer to internet coverage

i know very little about any of this so advice welcomed