WP 5.8.2 Causing Intermittent Slowness

I recently upgraded my main blog site to WP 5.8.2. Since then, I have notices intermittent slowness. My hosting company made several upgrades server-side, but none stopped the intermittent slowness. My normal, average load time (front page) is ~2.5 seconds (and I’m fine with that). After the 5.8.2 upgrade, the frontpage takes anywhere from 2-seconds to 30 seconds to load. There’s no rhyme or reason, though sometimes, pixel.wp.com comes up as the source of the waiting.

On my sandbox site (test.astronerdboy.com), it too was upgraded to WP 5.8.2 and has the same issues. I’ve been working there to see if the problem gets solved, including shifting to a WP-supported theme. I’ve run through the different plugins to see if any one causes an issue. Dropping all plugins does seem to alleviate the problem. HOWEVER…

I have two sites still on WP 5.8.1 (tenchi.astronerdboy.com and blog.astronerdboy.com). Both have nearly identical plugins as the anime and test sites. Neither the tenchi nor blog sites have any intermittent slowness issues. All four sites are on the same VM server. And after five days of working with my hosting support team, whereupon my VM is in great shape, I’ve come to the conclusion that there has to be something in WP 5.8.2 that is causing this problem.

The page I need help with: [log in to see the link]