FPS constantly slugging down to -10FPS

[miaou_ml]

I've been having this issue for a good couple of months now. When I first log into the game I'm always able to get clean 60+ FPS, but then I will get bunch of sudden spikes of slowdown after loading into the game, consistently every 3-4 seconds, where FFXIV becomes a slideshow, complete with input lag as well.

This ONLY happens with FFXIV, I've never had this issue with any other game I own, including games with more intense graphics/with many players (Fortnite, Baldur's Gate, Overwatch etc. all run without issue). It's honestly been making my game nigh-unplayable, so I'd like to know what else I could try to fix it.

Here is what it looks like happening. OBS does not affect my framerate in any way.
https://youtu.be/Nn602e-a_1g

I have already tried the following:
-Made power profile high performance
-Set FFXIV to high priority in task manager
-Updated all graphics drives + restarted computer
-Updated laptop firmware
-Uninstalled and reinstalled graphics driver with DDU
-Ran FFXIV in a clean boot
-Lowered graphics settings (FPS stays the same regardless of where I put it)
-Switched between DLSS and FSR
-Checked for overheating (CPU is consistently at 44C, GPU at 80C)
-Disabled Vsync
-Set FPS cap to screen refresh rate using all 3 possible methods
-Closed down all background apps
-Unplugged extra devices/controller
-Disabled controllers in FFXIV
-Disabled all plugins and overlays
-Disabled fullscreen optimizations
-Disabled windowed optimizations
-Disabled Microsoft Device Association Root Enumerator
-Disabled Hardware accelerated GPU scheduling
-Disabled Discord's hardware acceleration
-Disabled Game Bar (to the extent I could)
-Replaced faulty charger
-Restored game files/integrity check
-Rolled back to Windows 23H2
-Rolled back graphics driver
-Port-forwarded what Square asked me to
-Disabled Microsoft Edge

Specs:
Razer Blade 17 (Gaming Laptop)
Microsoft Windows 11 Home 10.0.26100 Build 26100
12th Gen Intel(R) Core(TM) i9-12900H 2.50 GHz
GeForce RTX 3080 Ti Laptop GPU (Razer Blade 17)
32GB RAM, DDR5 2500MHz
Samsung SSD, 1TB
Internet speed: 339.6Mbps download, 11.8Mbps upload