There are some BSD communities on Lemmy/kbin, but they don't have many subscribers yet.
Here are the ones I know of: @openbsd @openbsd @bsd @netbsd @bsd @freebsd @freebsd @netbsd @bsd @freebsd @FreeBSD
you're more likely to find BSD communities on reddit, each projects mailing lists, freebsd forums, and unitedbsd.com (which is a great forum, although not too active).