BTW, this same problem is already in bugzilla at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272642 . I too am experiencing it, on a system that I upgraded with freebsd-update from 13.2-RELEASE to 14.0-BETA4. And I'm at a loss to understand what's going on, because elfdump -a /lib/libc++.so _does_ show that symbol as present.
-Alan