I'm now getting 50% or so packet loss on hop 3 whilst running the game with ping plotter. Is that notable?
When you send through a lot of traceroute requests, some routers decide not to respond. If you take the interval out to 60 seconds (instead of 5 seconds) the router will probably honour a higher percentage of requests. They're just routers doing their jobs; traceroute requests are kind of a side show. We're peeking under the hood at the internal behaviour of the hops, but we'll have to apply interpretation to the information coming back.
The end result that matters is the roundtrip; if we can work out reasons why the round trip is wonky, we can potentially solve them.
[ or... what he said ^]
Doesn't look like my router has QoS unfortunately, only bandwidth control. And I couldn't set up the monitor, just shows packet loss.
Unfortunately it doesn't seem to be the case, the V2 has it, the V1 doesn't. I've opted for a VR600 V2 this time around (as opposed to the VR400 V1).
Re quality meter, did you have DOS protection enabled in the router? IIRC (it's a long time since I used a TP-Link) if set on high the quality meter won't work as it blocks the pings from Think Broadband, a lower setting should allow it.
Having become grade 2 obsessive about QoS, be aware that implementations vary.
The behaviour you want is low latency for a comparatively small volume of traffic. Priority is everything. Jumping the queue (the buffer) is everything.
Counterintuitively, QoS implementations achieve best performance by dropping packets and having small buffers; the buffer swamping packets from the low priority download are dropped and the sender quite happily shrugs and retries. If you find yourself wanting to split the hairs between your DSCP and your fq_codel, come back and ask and I'll tell you what you need to know.
FWIW, gaming may be the requirement best served by consumer grade equipment. The fuss in setting up badly documented port forwarding may make UPNP your best friend. Last general comment is that a "hifi" separates approach gives the ultimate control but is more fuss to find a way to house it. You're busy shopping for the router with the special blend. S/h modem and some other choice parts may not cost more than a one box solution but always is more fuss to install and keep the cables tidy; power consumption usually costs more than the purchase price differential in the long run.