Protecting your site from brute-force attacks, limiting login attempts, limit login errors from showing can be a pain to deal with on your child sites.
There is a very recent plugin called GuardGiant which handles a whole number of those security features all in one easy to use plugin.
After you have installed and activated the GuardGiant plugin it will add a new admin menu;
GuardGiant > Settings
GuardGiant > Whitelists
GuardGiant > Captcha
In the captcha settings of the GuardGiant plugin, it will use either the v2 or the v3 versions of Google reCAPTCHA.
GuardGiant > General Settings
GuardGiant > Activity Log
Lost passwords attempts from valid real users will not be locked out using the log in limit feature in the GuardGiant plugin.
The GuardGiant plugin using a number of custom database tables for storing its data in;
GuardGiant works with load balancers and CDN providers like Cloudflare. The GuardGiant plugin has no costs and is free to be able to use it. You can reduce the amount of extra bloat by using certain security plugins where you may not need all of the features provided and going with a minimal clean plugin option like GuardGiant.
GuardGiant plugin is well worth using on any child sites where you are not already using a security plugin on them.