Any way to have /wp-admin/ redirect to /wp/wp-admin?

You could perhaps set up a redirect in your htaccess, or if using nginx an nginx rewrite.

BUT, I actually consider this enhanced security. Less bots will look for site.com/wp-admin than site.com/wp/wp-admin. It’s a slight difference, but not that difficult to remember.

If you need it though, set up a redirect.