You're having quality of service issues getting across Missouri and into Level3's exchange in Dallas. Apparently, Charter has been having a lot of problems around St. Louis for some time now, amongst other areas:
https://downdetector.com/status/charter-communications

(this thumbnail is an archived image, a larger and more current map and more details about Charter's problems are available at the URL above)
You need to be in touch with Charter's Tier3 guys, as it is most likely an issue occurring upstream from where the localized Tier1/Tier2 techs can properly investigate and address. You will need to push specifically to talk to Tier3, and if they can't/won't escalate you--demand to speak to a supervisor until they do. Alternatively, you may find you get to them faster if you go through their online support channels. Some key things to mention:
You are experiencing excessive lag and elevated packet loss along specific routes.
You have run traces that show potential signs of elevated congestion or other issues along those specific routes.
You can provide those reports for a technician to review.
Run some tests to other known services as well. I will provide a link to a post from Blizzard support for their games so you can hit some of their servers if you like. But, it may prove useful to run traces to other things like Google/YouTube, TwitchTV, Netflix/Hulu, Microsoft, etc. So you can provide a good contrast of what is going on. The point you are trying to show is that it is not an issue with hops close to you, but further down their routes that they need to address.
Here is the link to Blizzard's guide for testing connections:
https://us.battle.net/support/en/art...g-a-traceroute
The usual script is to look at local connectivity, maybe send a tech on-site, and verify that your connection is good. That is not what is typically at issue here. Local connectivity into our ISP's localized network segments is typically good. The problems are most often creeping in along the path to the peering/transit exchanges that our ISP's have set up for us so that we can connect to other people's networks. This is all set up and maintained by our ISP's. It is their policies that determine the routing partner you use to get to Ormuco In Montreal (they have at least 3 they can choose from, up to 5 that Ormuco peers with directly). Their policies are also determining the specific route you take to get to those exchanges as well (in this case, Level3 in Dallas). Note that when you traced to the other world service, your route changes slightly in some points, and at some of those points the response times were much better. That is your ISP's policies in play making those routing decisions---nothing to do with SE.
You are paying them for internet service... with that comes the burden to ensure some level of quality of service to the internet. The internet is NOT just their local network, but a myriad web of other people's networks all interconnected at various points. That is basically why it is called the internet... as in inter-connected networks. It is their responsibility to monitor and adjust their routes when necessary to maintain the quality of the service you are paying them for...so don't back down on them. Demand better. If you press them hard enough, they should do something about it--whether that is fixing things within their own network, working with Level3, or switching you to someone else like Cogent, TATA, or any other higher tier ISP like XO or ALTERNET (Verizon). If not, you may want to look into alternative service providers.
Many are not aware that some companies actually lease local access from the big guns like Charter and TWC to get you to their servers in somewhere like Atlanta where you get switched into their networks. So, you may have options you may not be aware of. It may be worth investigating other names like Earthlink, Virgin, Century, etc. just to see if they have service in your area. In my case, Earthlink uses TWC here (and can still use your own modem), and actually charges slightly LESS for the same level of service. When I told them I was going to switch a few months back, they dropped my rate and we had bucket trucks up and down the street and they FINALLY tracked down the bad devices that were killing signal each night around 11:00. You'd be surprised how quick they are to take action once you tell them you are going to switch.
Just to show some contrast on the routing, I'm pasting in a current trace to my lobby server. It is pretty clean (atm at least, it gets wonky on the other side of Atlanta within Level3's transit a little later at night). This is NOT how it was a year ago. It took some time, and a good bit of tracert and modem signal/log dumps to the TWC help email address, but eventually we got things hammered out to the point that when my route goes bad I just sent them another log dump and within a few days they get things cleaned up. Most of the time, it results in a reboot of my modem and I either get my IP changed to a different gateway (currently assigned to one reserved for Conway, SC even though I am almost an hour away in Florence--why the ping is so high to first hop), or they just change who I use for transit to Ormuco (typically it's Cogent, or TATA...strange to see me on Level3 still after almost 3 weeks since they usually fall apart after about a week).
Code:
Tracing route to neolobby02.ffxiv.com [199.91.189.74]
over a maximum of 30 hops:
1 1 ms <1 ms 1 ms LPTSRV [10.10.100.1]
2 20 ms 25 ms 26 ms cpe-075-176-160-001.sc.res.rr.com [75.176.160.1]
3 26 ms 26 ms 23 ms cpe-024-031-198-009.sc.res.rr.com [24.31.198.9]
4 18 ms 18 ms 19 ms 24.31.196.212
5 25 ms 26 ms 27 ms be33.chrcnctr01r.southeast.rr.com [24.93.64.182]
6 27 ms 29 ms 31 ms bu-ether44.atlngamq46w-bcr00.tbone.rr.com [107.14.19.46]
7 24 ms 26 ms 27 ms 0.ae2.pr0.atl20.tbone.rr.com [107.14.19.11]
8 * * * Request timed out.
9 65 ms 65 ms 65 ms ae-11-11.car2.Montreal2.Level3.net [4.69.141.1]
10 65 ms 64 ms 63 ms ae-11-11.car2.Montreal2.Level3.net [4.69.141.1]
11 70 ms 65 ms 66 ms ORMUCO-COMM.car2.Montreal2.Level3.net [4.59.178.74]
12 49 ms 49 ms 51 ms 192.34.76.10
13 52 ms 52 ms 52 ms 199.91.189.242
14 49 ms 49 ms 48 ms 199.91.189.74
Trace complete.