I ran into the same issue, but was able to keep the up-to-date homebrew releases and maintain
homebrew upgrades Python from 3.6 to 3.7 as part of the
vim upgrade (not sure what toggle is needed to prevent that). When that happens, you'll "lose" all of your
pip modules (they aren't lost, they just aren't ported to the new install path, best to
pip3 freeze > pip3.txt prior so you can easily restore your working module set).
Next, to get
vim to launch properly, I needed to run a reinstall of perl in homebrew. This re-ran the
make install steps, which I am guessing provided the library links vim was looking for.
I had originally got a different machine working with the
brew switch ... method for moving back to Perl 5.26.2, but that wasn't working on this host. The reinstall did work, however. Now the up-to-date
vim launches properly alongside the up-to-date