@pimeys
You cannot follow Lemmy users, only communities. AFAIU, Lemmy just does not do anything with that request.

To share my experience : my Friendica account is set up to automatically boost anything @Liwott produces, and it does so as soon as this instance is aware of the Lemmy posting, but that does not always happen automatically. Sometimes I have to search my Lemmy post on Friendica, and only then it is boosted. Note that I do follow my Lemmy account from here