TIG gave you the right information about the membership.

@dhlscape said:

The PathCopy extension in the SU warehouse is not compatible with my 2021 version

It may not be listed as compatible but it works just fine in SketchUp 2021.
CLick the picture

@dhlscape said:

but sketchUcation has a JHS Powerbar plugin called Copy Along Path that I'd like to get.

FWIW, Copy ALong Path is available separately, too.