The current version of this addon (at the time of this post on 2/5/2022 Saturday) doesn't seem to be compatible with Blender v3.0.0, however version 2.0.4 does work in Blender v3.0.0. The current version on itch won't show up in the Addons list even after install in Blender v3.0.0. I solved this by using v2.0.4 of your addon instead.
The current version of this addon (at the time of this post on 2/5/2022 Saturday) doesn't seem to be compatible with Blender v3.0.0, however version 2.0.4 does work in Blender v3.0.0. The current version on itch won't show up in the Addons list even after install in Blender v3.0.0. I solved this by using v2.0.4 of your addon instead.