Tested this across browsers, essentially my site has a TTFB of about \~25s when visiting a page on the site. However, if logged in as a user, TTFB going to any page on the front-end is drastically reduced (<1s). Once logged out, TTFB goes back up to \~25s.

Unfortunately, I'm not able to troubleshoot disabling plugins since it is a live site for my company, and I can't recreate the issue when copying the site locally or to a different site on the server.

As for plugins, other than the custom ones we have set up (which may very well be the issue), we're using Gravity Forms, The Event Calendar, and Safe Redirect Manager. There's no caching plugin set up.

I set up a mu-plugin that fires under the option_active_plugins filter and disables ALL plugins on a page I define. Still crazy high TTFB, so I guess that rules out if the issue is a plugin (unless plugin scripts are still run prior to that filter, I am not sure)