Hello,
unfortunately im facing the same issue currently.
I upgraded my pc, went on 11 instead of 10.
After installing Premiere Pro 2023 I cant seem to install voukoder anymore. It installs, I reboot but it just wont show up in the dropdown list. Already tried repair option multiple times.
Edit: tried it with premiere pro 2022 and it worked right away. I didnt even have a plugin folder for 2023, maybe the 2023 version in general has issues with third party addons.