Wow Classic Raid FPS Issues

Hi.
I’ve been having issues for a while in Wow Classic (HC) while raiding.
When I phase in to 40 man raid I have around 200 fps (stable around 200 fps first few bosses).
Within 1 hour I’m down to 40-65 fps. Fps is getting progressively worse during the raid.
If I reload it does not nothing, if I exit Wow completely and open up the FPS resets back to 200 and starts gradually dropping again until complete lag.
I also play retail, no issues in RBG/M+/Raids on ultra settings.

What I’ve tried:
Reinstall Windows
Reinstall Battlenet + WoW
Remove all addons
Remove all weakauras
Reset UI (including defaulting all cvars)
CPU+Memory profiling addons during raid (Seems ok, some was removed)
Profiling weakauras during raid (Just simple buff tracker WAs loaded)
Switched DX11/DX12
Monitor GPU+CPU temperatures during raid (Also fine)
Buy new GPU (4080 Super)
Turn graphic settings to low/medium
Enable/Disable Windows Game Bar (Windows setting)
Enable/Disable Hardware-accelerated GPU scheduling (Windows setting)
Enable/Disable Optimisations for windowed games (Windows setting)
Enable/Disable target FPS / max fps in WoW
Upgrade all drivers (bios/chipset/gpu/etc)

Not sure what else I can test, or if I missed something in the list.

Specs:
AMD 5800X3D
4080 SUPER
1TB M.2 NVMe
32GB RAM

Does anyone else experience this in classic and how did you fix it?