You are absolutely correct, showler.
As someone who has actually read the source code of Vortex and developed a large portion of its game support codebase, and understands how Bethesda games load mod plugins, you absolutely do NOT need Vortex open for mods to work in ANY Bethesda game.
You can launch the game with SKSE directly from the game folder and everything will work fine. I do it all the time.
In any event, Vortex 1.14.7 has fixed this issue with the plugin-management extension:
https://github.com/Nexus-Mods/extension-plugin-management/pull/48