Just to fill in some blanks....
My RT-AX88U has F/W 384.19 (I know it is old, but it is stable). I did roll back to 384.18 just to check, and install a fresh copy, and it still rebooted.
It sits behind my ISP router, and the WAN IP is 192.168.0.1, with an internal LAN range of 192.168.0.x
The windows 11 laptop is the only device that seems to trigger the router to reboot. Other wired and wireless Windows 10 and android devices (and Iot devices) do not trigger this.
I've investigated as far as I can on the laptop side (updated and/or replaced drivers), run the suggested commands from MS. It still happens now and then and does not seem related to a particular task.
I do run Chrome, do not keep tabs open, do close the lid to let the laptop sleep (no issues when sleeping). I have ublock origins plugin and gmail checker only. I've had a reboot without Chrome running, so do not believe it is related.
I do allow and install all available MS updates.
I don't run any additional anti-virus.
Since this seems to be a larger issue, and others have reported no effect, I'm not going to bother reconfiguring the router from scratch at this point.
Very strange. Started roughly a month ago. Based on the feedback so far, I blame MS