Laggy video caused by effects

System specs:

-Azus Zephyrus Duo 16 (2022)
-AMD Ryzen 9 6900HX
-Nvidia GeForce RTX 3080 Ti (laptop)
-32GB RAM
-Windows 10 Pro 22H2 (Clean install and also on Win11 Pro 23H2 with same hardware)
-Samsung 990 Pro 4TB
-Premier Pro 24.3.0 build 59
-Source File type: insv (Insta360, using plugin for Premier Pro)

Issue: Playback during edit is buttery smooth except when playing back video transitions. If a dissolve in (for example) is encountered in a clip, the video suddenly becomes very laggy, missing frames.
Stopping and resuming playback smooths back out the playback - but you don't get to preview the effect this way.

Troubleshooting steps:
-Delete Cache
-Reduce playback resolution
-Turn off HD playback

-Try different renderer (OPENCL)
-Clean boot Windows to make sure nothing else is running
-Latest drivers and OS updates
-Downgrade to clean install of Windows 10 with no manufacturer utilities or bloatware.

Any ideas here?