Disk performance can be a problem under WSL2, I ended up switching to Workstations after running into this issue: https://github.com/microsoft/WSL/issues/4197

Seems to more of a Defender issue than a WSL one, see https://github.com/microsoft/WSL/issues/8995

After adding exclusions for the fsnotifier-wsl process and and both variants of the WSL distro path my disk performance was improved.

Adding the idea64.exe process also helped since I was trying to run IntelliJ against projects inside WSL.