Belkin router issue, signal distance not as advertised

Recently bought a Belkin AC1200 because our 3.5 yr old netgear was starting to have issues. Claimed to throw signal out something like 200 ft, and had some kind of tech where if a device was pulling signal from a certain direction, it would concentrate long range in that direction to up the power.

When we first moved in, we got service from the cheap netgear router no problem, but the past 6 months or so, it had dropped considerably. The box on this Belkin, and the internet, claimed that AC alllowed for much stronger long range signal, so we bought it.

However, it's not any better than the netgear was. I can get somewhat ok signal on my phone and laptops in the bedroom, but on our Roku1 its laughably bad.

Also, this router doesn't seem very fast. I remember when I had 15mbps internet and it was by far the fastest anyone could get at the time. Never lagged, playing on Xbox live I always had host. Now I supposedly have 64mbps/5 upload, and speed tests say I have 65/6, but I have issues on a fairly consistent basis with buffering while streaming, certain websites taking forever to load, and other signs.

Lastly, it will randomly drop one of the dual band lines sometimes. But the other still works. Mostly the 5ghz that gets dropped. Never seen that issue before.

Did I get a dud, or do I need to figure out a different solution beyond the router? Been leaning toward the answer being both options, personally.