I've split the following from my reply in Re^2: On improving Perlmonks site availability to avoid to much thread-drift, but would be interested to discuss this, at least in theory.

What might be possible is to host a static mirror° at another site like github or gitlab pages (10 GiB content free) (which both must already have good bot protection and CDNs) and setup Apache config/.htaccess to redirect all visitors without logged-in cookies there.

Of course except when aiming for the login page.

Alas Anomonks would loose access to dynamic content like searching and posting then ... (hmm ... well at least at the beginning)

First test would be to see if a temporary block of anonymous requests on Apache level brought the desired relieve for logged-in users.

Worst case is the web server gets already exhausted with redirecting to an external "maintenance page", even before PM's Everything engine gets involved.

My hope is that the bots quickly realize there is another target IP.

°) NB: the named links in the static mirror would need to be rewritten to the targeted node-id, or we would need to store many pages twice. (Update: In hindsight replacing named nodes with symlinks should be easier and more robust)