internet connection delay

For about the last month, I've had an internet issue where the initial "connecting to [whatever URL]" step randomly takes a long time. Randomly as in not always, and not always the same sites. When I try to make it happen, it doesn't happen. The delay isn't always the same length. But it happens many times a day. Once past that initial delay, the page then loads quickly.

It has happened both at Qiao's house and my house; he's got a different ISP than me.
It has happened both on my personal laptop and work laptop, though I think I only noticed it a few times on the work laptop. Most of the time, the work laptop is connected to a VPN; it may have only happened when I wasn't on the VPN, but I'm not sure.
It has happened in various browsers (Waterfox, Firefox, not sure about the others)
Speedtest.net results show nothing unusual.

Do any of you know what could cause this or how to fix it?

Based on what I read on this page, I already tried turning off DNS over HTTPS but that did not fix the problem, so I re-enabled it:
https://www.reddit.com/r/waterfox/comments/qoc9ty/every_new_website_i_visit_in_a_new_session_takes/

... Found another post which might be related to my problem:
https://www.reddit.com/r/waterfox/comments/r76qg8/httpsgoogleapiscom_weird_slow_connection_issue/