To ensure you have done everything right:
You need SKSE version 2.0.20 (GOG or Steam, 64-bit).
Publish Date: 2021 Context
If you are looking to mod Skyrim in 2021, you have likely encountered the "SKSE" requirement. However, 2021 was a turbulent year for Skyrim modding due to the release of the Anniversary Edition. Below is everything you need to know to get the correct version running.