Any user or community just has to be prepended with lemmy:, for example hit Go to User and enter lemmy:efraimbart to view my profile. To view any community or user not on the default instance you can append @<instance> to it, for example lemmy:efraimbart@lemmy.world.

It is still in Alpha. Currently viewing communities, users, posts and comments of Lemmy instances mostly works.

Download links can be found here: https://sopuli.xyz/post/1103776

Have you tried Infinity for Everything?

Everything is a middleware that connects with multiple services and currently has early compatibility with Lemmy. See here.