trying to redirect in .htaccess unless it's an admin

I am trying to write a rule in .htaccess that redirects all /wp-admin to /login UNLESS a certain user (WebAdministrator) is logging in. How do I make such a rule?

If I use:

Rewriterule ^wp-admin /login [R=301,NC,L]

then it breaks it because it will keep redirecting to /login, even for the administrator since when the administrator logs in they are supposed to see the panel at /wp-admin

You have a chicken-and-egg problem. You don't know if a user is an administrator until he is logged in, so you don't have the information to make conditional redirect before login.

There are a couple of ways to do this in apache, but none are great.

The best way is to do this in wordpress instead, either building a tiny wordpress plugin to change all wp-login.php (the login page location) to your custom /login using the relevant hook: https://developer.wordpress.org/reference/hooks/login_url/

The only ways an apache rewrite could know if someone is logged in would be to ask wordpress or read the cookie directly.

For the former, you will want a custom script running from the rewrite module using RewriteMap's PRG mode (https://httpd.apache.org/docs/current/rewrite/rewritemap.html#prg) to run a PHP script that queries wordpress' authentication system to see if they're logged in, and rewrite appropriately.

You can also check against the cookie value directly by using a RewriteCond based on the HTTP_COOKIE variable (see https://httpd.apache.org/docs/2.0/mod/mod_rewrite.html#RewriteCond)

Both of these are extremely brittle hacks, however, and I'd highly recommend doing it in WP instead.