I am unable to use gvim with vim-8.2.3458 because it has no GUI support compiled in. I have reverted to .3081 which does have gvim and GUI support.
This is intentional, see: https://lists.freebsd.org/archives/freebsd-ports/2021-August/000496.html You should be able to install vim-gtk3 and get gvim. Please re-open if not.