Huge ping spikes that only occur in FFXIV and not in other games.

[GreatGoblin]

Hello folks, in all of my days I have never felt so stumped and defeated by a technical issue.
I have always been able to figure a vast majority of things out myself but this is an absolutely harrowing exception.
For context me and my girlfriend play FFXIV together in the same room 5 ft apart and are connected to the servers through wifi, we both use the exact same make and model of wifi adapter and we have even swapped them so that she is using mine and I am using hers but the problem remains the same.
The problem therein is that, while I play the game with 30 ping and zero lag spikes ever she plays it just 5 ft away from me and can hardly maintain a connection, she pokeballs every 10-15 seconds, teleports around and disconnects frequently, the latency is so bad that she has problems not standing in simple ARR mechanics.
When it comes to hardware she has me beat and can easily run the game on max settings and load into Limsa in just a few seconds (a task that often takes me several minutes) but her internet connection is absolutely dismal and I cannot for the love of Yoshi P. figure out why or how to fix it.
It is 2 AM.
We have tried everything under the sun in the past three or four days and I am at my breaking point.
We have tried in vain attempt to resolve the issue time and time again with no luck, stated below is a laundry list of things we have tried that hopefully can serve to evade redundant advice which includes but is not limited to:
- Accepting both First Party and Third Party Cookies.
- Allowing software to run or install even if signature is invalid
- Making sure that all SSL and TLS are CHECKED and that SSL 3.0 is unchecked
- Restarting the PC in question.
- Running the game as Administrator
- Making sure windows firewall is not interfering with the game or that it is not being otherwise sabotaged by Bill Gates.
- Ensuring that that port ranges
54992 through 54994,
55006 through 55007,
55021 through 55040
are open on our router.. 
- Flushing DNS
- Reseting TCP/IP
- Deleting the Patch Folder
- Changing the local DNS server to 8.8.8.8 and 8.8.4.4
- Deleting local files with potentially corrupted character data to be redownloaded.
- Resetting network settings to default
- Preventing power saver mode from interacting with the network adapter
- Running the game through a VPN
- Plugging the wifi adapter directly into the motherboard
- Turning all in-game settings to their lowest fixtures.
- Reinstalling the game
- Restarting the router
- Swapping to a brand new network adapter
and many MANY other things which I have neither the recollection or mental fortitude to list.

Lastly I would like to express my thankfulness for ALL input and advice regardless of whether it solves the issue or not.

Thank you for reading through my woeful epilogue and taking the time out of your day to provide assistance to a perfect stranger.

[ZitiPenneBean]

Hello, I am said girlfriend in question. Before anyone suggests, there is not any logical way right now for us to try a wired connection. The router is located in another room and unless we find a cable long enough for drill holes in the wall, it's not happening.

[Burnt_Bottom]

Hey, I see that unfortunately no one has replied to you regarding your issues. Unfortunately I do not have an answer either but wanted to reach out since I'm in a similar situation. For whatever reason I have high and inconsistent ping compared to my boyfriend. I haven't gone through the extensive list of possible soluttions as you have but my hunch is that it's unlikely they would resolve my issue as well. Just wanted to reach out to let you know you're not alone and to maybe see if you've come across a solution?

[DarkArvan]

You can not change it on your end, its all up to your internet provider and the route its using to the ffxiv server / tier 3 carrier from Square Enix. Contanct your provider and deliver them traceroutes with the issue.
you can also provide Square Enix Support with trace routes. see here: https://forum.square-enix.com/ffxiv/...t-Loss-and-Lag
Port Forwarding, firewall settings, pc setup etc. has no outcome in any improvement on internet routing.