Constant ping fluctuations for the last month.

Not to be a pest, but would you mind running one more test to:

wdc.login.pathofexile.com

instead of to the patching address from before. I'm assuming based on your location you try to play on the DC gateway, yes?

The one thing that concerns me is the the difference in average latency before you enter network layer hops, to the final hop. In the run you did, your last hop on shaw cable saw your average latency at 48ms. This is a touch high for the middle of your route, but certainly playable. Lockstep may still even work okay.

After that you enter network layer hops, which should impact your latency pretty minimally. However, by the last hop you see an average latency of 71ms. That's not terrible either, but it is a bit of a jump. I'd like to see when happens when you are trying to run a test to the DC gateway while playing.

If you don't mind, that is.

I'd agree that the situation you are describing is quite different than what your WinMTR results indicate they should be .

Has your security software completed a patch recently? If it has, or it is possible it may be interacting negatively with your ability to play, I'd suggest adding PoE as an exception. I'm not entirely confident that is what's going on though.

Those results look very different / much worse than before. You are seeing large latency spikes at every hop and your average response time is all over the map. Much of it would be traffic mitigation, but there is something off about all that.

I know you've been asked for a lot already, but would you mind running one final test?

I was thinking to a known good location, for comparison. Generally, I suggest the public DNS address of Google found at : 8.8.8.8

It's easy to remember, and it should be solid as a rock. If you are seeing numbers like you just posted to that address, we know it is something to do with your service.

Do you see any problems with latency in any other applications / games?

It could be a sign of an issue with a problem with an over saturated link your ISP is using. It might be worth giving them a shout to talk to a 2nd level tech about fluctuating latency to multiple locations and known good locations.

They should be able to help you figure things out. I don't think this is a local issue, because things seem stable to your home router. It's possible something on your home network is causing problem, but I think an issue at the ISP is more likely. Just my viewpoint though.