System Information
Operating system: Windows 10
Graphics card: RADEON RX5700 TX

Blender Version
Broken: 2.83 LTS
Worked:

Short description of error
Blender 2.83 EEVEE freestyle greyed out

Exact steps for others to reproduce the error

If below checkbox is not checked under Cycles Render Setting.
View Layer Properties -> Filter -> Freestyle
You will not be able to use freestyle in EEVEE.
It is not straight forward or there is no hint for the user to figure out what happened.