Yea, for some reason following groups like lemmy communities and others seems broken. Others are aware and I don’t know where that’s up to in terms of a fix.
As for antennas, my experience is not to get your hopes up with them. Generally, anything moderately complicated/useful is unlikely to work. Their main use case, AFAIU is to apply boolean logic to hashtags. Additionally, you can define the source of posts that the logic will be applied to. Anything beyond that and you’ll be fighting the feature.
In your case, I don’t think it’s possible to combine a specific source such as a community (which will be seen as a user) with all users seen by the instance. You either specify users or servers or everything as the source.
My post above was trying to hint at this in a general sense … don’t let all of the bling and features fool you into thinking it’s a super powerful platform. It’s got some nice things going for sure, but many of the features are closer to being proof of concepts than powerful tools you can wield to meet your needs.
The stuff that works well are:
UI, which looks nice and is customisable (except on mobile where it’s too cluttered and small for many including myself)
Markdown (MFM specifically) with provides fun animations and other unique features. Add longer post lengths and reaction emojis to this too.
reply threading
clips (groups of bookmarks which can be made public, which is oddly useful given how simple an idea it is)