Extreme FPS lag spikes & Slowmotion -> Fast forwarding gameplay due to ping spikes

The video at the bottom is not slowed down. This happens when the ping ping-pongs up and down for some odd reason in some instances. Once the lag breaks free, you are "fast forwarded" for x amounts of seconds where your character is unable to move until the game catches back up.
You can also see in the video, my FPS is ping-ponging like crazy.

I have a monster of a PC, last league I ran full high/ultra with stable 144fps.. This league, even though I tried lowering the settings, it keeps spiking leading to a stuttery gameplay. Very annoying. Even in my hideout or in act 10 town.

I tried fully removing the GPU drivers with DDU and installing an older version, 25.9.2, no improvement.
Redid it and installed latest version, still having issues.

Specs:
CPU: AMD Ryzen 9 9950X3D
GPU: Radeon RX 7900 XTX 24GB OC NITRO+
Disk Drive: Samsung 9100 PRO SSD
RAM: CORSAIR VENGEANCE DDR5 64GB (2x32GB) DDR5 6000MHz CL30
CPU cooler (AIO): ARCTIC Liquid Freezer III 360

CPU load stays steady around 25% when in map.
GPU load fluctuates from around 50% to 90%
Temps are normal, around 60 degrees celsius.

I have tried turning on and off, lowering all settings but see no improvement when the stuttering appears. I can reach almost 200 FPS if I uncap my framerate, but the FPS seems to ping pong down to 10 FPS and up again.

My current settings are:

Mode: Windowed fullscreen (tried fullscreen, no difference)
Render resolution: 77% - 1970x1108 (tried changing to all different kinds, no difference)
Renderer: DX12 (tried Vulkan aswell, same issue)
VSync: Off (tried turning on and same issue)
Triple-buffering: Enabled (tried turning off, no difference)

Antialiasing quality: Low (Had it on high before and still lagged)
Upscale mode: NIS (Had FSR before, same issue on FSR)
Lighting: Shadows (Had shadows + global illumination before, no difference)
Shadow quality: High (Had ultra before, no difference)
Sun Shadow quality: Low (had high before, no difference)
Number of lights: High (tried lowering to Low, no difference)
Depth of field: Disabled (Tried enabling, no difference)
Water detail level: High (tried low, no difference)
Texture quality: High (tried medium, no difference)
Texture Filtering: 16x (tried triliear & 4x, no difference)

Dynamic culling: Enabled (tried disabling, no difference)
Dynamic resolution: Enabled (tried disabling, no difference)
Target framerate: 60
Engine multithreading: Enabled (tried disabling, lowered performance, increased CPU frame time by 10ms)

So it seems like there are 2 issues at hand:

1. Some kind of network issue (am from EU and tried different gateways, Frankfurt, Amsterdam, London) and am experiencing the slow motion due to ping spiking up and down on all of them.

2. FPS spiking issues with unknown cause. (EDIT: Seems to stop FPS spiking after I stop streaming on discord)

I will leave a link below to the video I recorded of my mostly empty map. It was slightly improved inside the mirage but still stuttery.

https://youtu.be/zu6R5-F1xK8