R7000 max speed problems (300mbps?)

TL;DR: 275 Mbps is pretty good at 5 GHz

Keep in mind that there is difference between link speed and throughput.  Link speed is the physical connection rate whereas throughput is the rate of useful data transfer.  Throughput is always less than link speed due to protocol overhead, data loss and congestion caused by other nearby Wi-Fi networks and devices.  On Wi-Fi, it is not uncommon for throughput to be no better than 50% of the link speed.  Often, it is much, much worse.  The speeds used in router configuration and Windows adapter settings are link speeds.  The speeds reported by speed tests are throughput.

I don't know what's going on with Acrylic.  Maybe it doesn't know how to report 802.11ac link speeds.  Anyway, if your testing machine is reporting a link speed of 867 Mbps then it's probably using a 2 antenna Wi-Fi adapter.  The R7000 is a 3 antenna Wi-Fi router.  Your PC's Wi-Fi adapter won't be able to connect at a link speed of 1300 Mbps.  867 Mbps is the best the PC can do.  3 attenna adapters are very rare.  Last I heard, only Asus makes one.

If you look at the revised test measurements of the R7000 on smallnetbuilder.com, you will see that the reviewer was only able to achieve a maximum throughput of 530 Mbps using back to back R7000s.  This was achieved with 3 antenna setups where both routers were sitting next to each other.  At longer distances, throughput dropped off significantly.

If we use 530 Mbps as a maximum, practical throughput, a simplistic guess of what a 2 antenna Wi-Fi device can achieve would be 2/3rds of that or 353 Mbps.  This assumes a near perfect environment.  At normal distances, throughput is going to be significantly less than 353 Mbps.  If you are able to get 275 Mbps, I'd say you're doing pretty well.