It used to be required for just watching as well.
But it has been made available for free at the beginning of the COVID epidemic. I was not sure if this was to stay that way indefinitely.
But the current FAQ says watching is free, so I guess it may stay that way.
https://support.plex.tv/articles/226463767-frequently-asked-questions-dvr-live-tv/
To answer the original question again, in a different way:
No, Plex Pass won’t change a non-working remote access. I can only point to The Basics of Remote Access Troubleshooting
