Update - this did not fully solve the issue, still seeing disconnects.
And interestingly more as the weather is getting warmer or the printer bed is hotter (ABS vs PLA).
After some debugging today, once the disconnects start, reconnecting a toolhead fixes it only for a few minutes, until another toolhead randomly dies.
A printer power cycle restores it to normal operation. My next suspect is the USB2CAN chip becoming glitchy when hot.
Moved it right next to the intake fans, will report how it goes.
