if you can't copy long path names it has nothing to do with copy or robocopy, it is a limitation of the windows filesystem, so i am afraid even if you manage to find something willing to do it (it is possible, i have seen it done) you will get files that are inaccessible and so useless.
story about seeing it done, it was on windows server 2016 at least (idk for other versions, it was what we had where i worked) possible to, using SMB, create situations where by coping/moving a folder the files in the folder would end up past the path length limit server side, and so become lost as the server had no way of accessing them. i had to find a copy of those files from before the move to get them back.