sfx2000
Part of the Furniture
Your best bet for improving range using a single router is to use an AC class router with as many transmit receive streams as your budget allows. Right now this is 4x4, which means AC2600 or AC3100. AC5300 doesn't buy you range with its second 5 GHz radio. It can help increase capacity.
I would agree - however the best approach is put the AP's, if possible, where the users generally gather - as physics is a real thing, and no amount of big-honking routers will solve that, as the client side is pretty much what it is...
3*3:3 (and now we see 4*4:4) AP's do help, as there is some gain to be had, even with single stream clients, but it pales in consideration of proximity to the AP...