CMS: WordPress
Theme: Astra base (free), customized for AAR with Elementor pb, updated for a more responsive design on both desktop and mobile
Site Speed Improvements: CDN, gzip, cache, lossy/lossless and adaptive images, lazy-loading images, WebP images, on-the-fly processing, flying pages (replaces Quicklink), unloading assets per page
Back-end improvements: white-labeled, reordered menus for ease of admin navigation, custom shortcodes built into functions, anti-spam, backups, custom user roles, built-in analytics

Things that add no real value but are super-fun anyway: Responsive mega-menu, accordions on various pages, off-canvas on various pages, dancing “donate” button, custom Google Maps appearance, auto-updating copyright in footer for less website babysitting