I did not enable DNS over HTTPS. I was using DNS settings from access control and not from internet settings, at least initially. I did try using internet settings for DNS and using system default setting in access control. I tried changing the bandwidth setting.
It happens with both 5 and 2.4 GHz. If there is a pattern I’ve yet to find it. And since I need a stable connection during the week I couldn’t test it until this weekend.
There is one other thing I noticed but since I wasn’t really paying attention I’m not sure how accurate it is. When I switched back to your router, I initially did a test of video conferencing (using jitsi) and it seemed to be fine. Other members of family used Zoom. Initially they didn’t notice but over time, it seemed to become progressively worse (more frequent pauses).