Performance Issues since Necropolis League

Been playing the game for a decade without any problems. I typically run at the highest settings and aside from certain builds, like CoC DD, I've experienced no lag, fps drops, or rendering issues.

At the start of Necropolis league I started experiencing massive spikes in FPS loss seemingly at random. It occurred in all towns and maps but was not present in the hideout or mine. I lowered all my settings and disabled a number of sound options and it stopped stuttering everywhere but in towns.

At the start of Settlers the FPS drops have returned as well as new rendering issues. This happens again in all towns and maps, even when running no extra content. Sometimes the ground texture for the towns does not render, the blood in Blood Aquaducts appears blue and transparent, and the Sacred Grove takes a solid 5-10 seconds to render anything, every time. Sitting in hideout I maintain ~144 FPS but in maps it will spike to single digits every few seconds in combat. Town consistently spikes between 165fps, 110fps, 70fps, and as low as 20fps seemingly at random.

I am playing Mjolnir Archmage utilizing Ball Lightning of Orbiting and CWC Lightning Warp.

MTX:
Tormentor Helmet
Poltergeist Shield
Tormentor Body Armour
Eyrie Weapon Effect
Tormentor Gloves
Tormentor Boots
Tormentor Portrait Frame
Steam-Powered Portal Effect
White Cyclone Effect

PC Specs:
Windows 10 Home
Motherboard: Gigabyte Z390 Aorus Master
CPU: Intel Core i9-9900KF
GPU: Nvidia RTX 2080Ti (MSI Gaming X Trio)
RAM: 32GB (4x 8GB Corsair Vengeance LPX DDR4-3200)
SSD: 1TB Seagate Firecuda 520 M.2 PCI-E 4.0 NVME Gen 4 SSD - Gen4 Read: 5000 MB/s, Write: 4400 MB/s, Gen3 Read: 3450 MB/S, Write: 2500MB/s

Render Resolution: 2560 x 1440
Renderer: DirectX12
VSync: Adaptive
Triple-Buffering: Enabled
Antialiasing Quality: Off
Upscale Mode: NIS
Lighting: Shadows
Shadow Quality: Low
Sun Shadow Quality: High
Number of Lights: Medium
Depth of Field: Disabled
Water Detail Level: High
Texture Quality: High
Texture Filtering 16x Anisotropic Filtering
Dynamic Culling: Enabled
Dynamic Resolution: Enabled
Engine Multithreading: Enabled