I ran another test via webpagetest.org (anyone can do this, by the way – it’s a free, public, and anonymous service). The test was run from the east coast of the USA. See https://www.webpagetest.org/result/211113_BiDcF1_bbeb8970aa292ef383ccb7338980cc2d/ . There was just one odd static asset (a PNG image) that took about a minute to download. It wasn’t blocking. Otherwise, the overall wait was only about 5 seconds! Way better.
Anecdotally, warm-cache page loads do feel way faster to me on desktop and mobile now. Very near the 5 seconds mentioned above. Cold-cache performance seems just as bad as when I originally ran speed tests ( see Help.nextcloud.com slow page load times ), though. It seems to be blocking for over a minute on several javascript files and static assets (png images). I also noticed piwik.js failed to load from stats.nextcloud.com–that may be because I use an ad blocker (Pi-hole).
Anyway, this is great progress! Thank you @anon75456558 and team!